jcahpo study set, coa study guide card updated

A hemorrhage that partially fills the anterior chamber with blood is called a. Hydrops b. Hypopyon c. Hyphema d. Hypophoria

C

A lens consisting of two cylinders of equal but opposite powers is the a. double cylinder. b. spherocylinder. c. cross cylinder. d. axis cylinder.

C

Advances in digital imaging technology facilitated the practical use of what type of dye? a. Trypan blue b. Rose Bengal c. Indocyanine green d. Gentian violet

C

A lens with a focal length of 2 meters has a power of a. 0.5 D b. 1 D c. 2 D d. 5 D

A

How are axial length measurements obtained? a. High-frequency sound waves through specific ocular tissue. b. Short light waves through specific ocular tissue. c. High-resolution cross-sectional imaging of internal structures of the eye d. Electrodes that measure electrical potential between the cornea and retina.

A

What is an important difference between soft and rigid lenses? a. Comfortability b. Closely fit to the shape of the cornea c. Durability d. Less susceptible to spectacle blur

A ​

If a patient must be kept waiting, convey a. their appointment was never scheduled. b. they should not complain. c. how long the wait will be and unfortunately, schedules cannot always be controlled due to emergencies. d. they should read the pamphlets in the waiting room.

C

Routine maintenance on the phoropter should NOT include: a. gently wiping off all exposed phoropter parts with alcohol. b. protecting the phoropter with a dust cover when not in use. c. cleaning the back lenses of phoropter with glass cleaner. d. cleaning off dust on enclosed lenses with an ear syringe.

A 1. protecting the phoropter with a dust cover when not in use 2. cleaning the back lenses of photopter with glass cleaner 3. cleaning off dust on engrossed lenses with an ear syringe

A disadvantage of chemical-based rigid contact lens care systems is a. Irritation b. Simplicity of use c. Poor disinfection d. Low replacement rate

A ​

In A-scan biometry, which ocular measurement provides the axial length of the globe? A. Anterior corneal surface to anterior vitreous face B. The distance between the corneal surface and the retinal surface C. Pre-corneal tear film to posterior pole D. Pre-corneal tear film to posterior vitreous face

A A-scan ultrasound biometry is used to determine the eye's axial length as well as the depth of the vitreous cavity, anterior chamber, and lens. The A-scan ultrasound is the most commonly used because as a critical part of the preoperative evaluation of cataract surgery patients.

The amoric environment in the operating room is created by all steps below, EXCEPT the a. use of powdered gloves. b. use of lint free drapes. c. rinsing of instruments after use with saline. d. use of millipore filters.

A Although powdered synthetic gloves do not present the risk of allergic reactions, these devices are associated with an extensive list of potentially serious adverse events, including severe airway inflammation, wound inflammation, and post-surgical adhesions, which are bands of fibrous scar tissue that form between internal organs and tissues. In 2016, the FDA published a rule banning the use of powder on surgical and examination gloves. While powder acts as a lubricant and helps you don and doff gloves more easily, they are linked to avoidable health risks including severe airway inflammation and allergic reactions such as asthma. STEPS, ADDITIONAL INFORMATION 1. Bring all required supplies to the OR. Sterilize or disinfect them as required., This step prevents the need to unnecessarily leave the restricted area.Movement in the OR should be kept to a minimum to avoid contamination of sterile items or persons. 2. State the purpose of your visit to OR personnel and show your ID., This step allows for clear communication with the health care team. 3. Artificial nails should not be worn, and nail polish should be fresh (not more than four days old) and not chipped., Artificial nails, extenders, and chipped nail polish harbour more microorganisms than hands and can potentially contaminate the sterile area. 4. Remove all jewellery. Wedding bands may be permitted under agency policy., Jewellery harbours additional microorganisms and must be removed prior to a surgical hand scrub. 5. Don surgical attire (top and bottom). Surgical attire must be worn only in the surgical area. Tuck top into pants., Surgical attire must be worn only in the surgical area to avoid contamination outside the surgical area. 6. Cover shoes according to agency policy., Shoe covers will protect work shoes from accidental blood or body fluid spills in the OR. Shoe covers must not be worn outside the OR area. 7. Perform a surgical hand scrub according to agency policy., Surgical hand scrubs reduce the bacterial count on hands prior to applying sterile gloves. Hands are kept above waist at all times. 8. Prior to entering the restricted or semi-restricted area: Apply mask.Apply head covering to cover earrings, beard, and sideburns.Once in the OR, introduce yourself to the surgical staff and inquire about the sterile area and non-sterile areas., Mask must cover nose, mouth, and chin for a proper seal. Mask should be changed if it becomes wet or soiled.A surgical mask or N95 mask may be required, depending on whether the patient is on additional precautions.Knowing what area is sterile/non-sterile will prevent accidental contamination of sterile fields and delays in surgery.STERILE PERSONS/AREAThe sterile field should be created as close as possible to the time of use. Covering sterile fields is not recommended.Sterile areas should be continuously kept in view. An unguarded sterile field is considered contaminated.Sterile persons should keep well within the sterile area. Sterile persons should pass each other back to back or front to front. A sterile person should face a sterile area to pass it and stay within the sterile field.NON-STERILE PERSON/AREAA non-sterile person should stay at least one foot away from the sterile field, and face the sterile field when passing it.A non-sterile person should not walk between two sterile fields or reach over the sterile field. Microbiology lab analysts generally use a Millipore filter in the form of a thin membrane in sample testing. These thin membranes are generally sterile and only used once. They are placed in specialized equipment such as filter funnels, removed when the water is all drawn through, and tested. Lint free drapes minimize airborne contamination and spreading of particles into the surgical wound. Standard of Practice V Drapes should be flame resistant. ​

What is the term used to refer to symptoms due to uncorrected refractive error? a. Ametropia b. Asthenopia c. Esotropia d. Anisometropia

A Ametropia refers to a group of visual disorders caused by errors in the refractive power of the eye. In a normal eye (emmetropic eye), light rays focus directly on the retina, whereas in ametropia, the light rays are not able to do so. Eye strain, also known as asthenopia , is an eye condition that manifests through non-specific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and occasional double vision. Symptoms often occur after long-term use of computers, digital devices, reading or other activities that involve extended visual tasks[1] which are broadly classified into external and internal symptom factors Esotropia is a condition where one or both eyes turn inward. The term derives from Greek, where 'eso-' means 'inward,' and 'trope' means 'turn.' Anisometropia (an-EYE-so-meh-TROW-pea-uh) is a vision condition in which one eye has more refractive error than the other. For example, one eye would be more nearsighted (myopic) than the other. So, that eye needs a significantly stronger lens correction than the other to see clearly.

The fluid between the cornea and the iris is a. aqueous humor. b. vitreous humor. c. choroid humor. d. ciliary humor.

A Anterior chamber - the fluid-filled space between the cornea and iris. Aqueous humor - the clear, watery fluid between the cornea and the front of the vitreous. The aqueous humor bathes and nourishes the lens and maintains pressure within the eye. The vitreous body is the clear gel that fills the space between the lens and the retina of the eyeball in humans and other vertebrates. It is often referred to as the vitreous humor or simply "the vitreous". The front of the choroid is the colored part of the eye called the iris. In the center of the iris ... gel-like fluid called vitreous humor or vitreous gel. The ciliary body is found behind the iris and includes the ring-shaped muscle that changes the shape of the lens when the eye focuses. It also makes the clear fluid that fills the space between the cornea and the iris.

1. The cones of the human eye are sensitive to which colors? a. Red, green, and blue, b. Green, blue, and yellow c. Blue, yellow, and red d. Red, green, and black

A Cone Details. They provide the eye's color sensitivity. The green and red cones are concentrated in the fovea centralis . The "blue" cones have the highest sensitivity and are mostly found outside the fovea, leading to some distinctions in the eye's blue perception. A special property of the cone system is color vision. Perceiving color allows humans (and many other animals) to discriminate objects on the basis of the distribution of the wavelengths of light that they reflect to the eye. While differences in luminance are often sufficient to distinguish objects, color adds another perceptual dimension that is especially useful when differences in luminance are subtle or nonexistent. Color obviously gives us a quite different way of perceiving and describing the world we live in. Unlike rods, which contain a single photopigment, there are three types of cones that differ in the photopigment they contain. Each of these photopigments has a different sensitivity to light of different wavelengths, and for this reason are referred to as "blue," "green," and "red," or, more appropriately, short (S), medium (M), and long (L) wavelength cones, terms that more or less describe their spectral sensitivities urrent understanding is that the 6 to 7 million cones can be divided into "red" cones (64%), "green" cones (32%), and "blue" cones (2%) based on measured response curves. They provide the eye's color sensitivity. The green and red cones are concentrated in the fovea centralis . The "blue" cones have the highest sensitivity and are mostly found outside the fovea, leading to some distinctions in the eye's blue perception. The cones are less sensitive to light than the rods, as shown a typical day-night comparison. The daylight vision (cone vision) adapts much more rapidly to changing light levels, adjusting to a change like coming indoors out of sunlight in a few seconds. Like all neurons, the cones fire to produce an electrical impulse on the nerve fiber and then must reset to fire again. The light adaption is thought to occur by adjusting this reset time. The cones are responsible for all high resolution vision. The eye moves continually to keep the light from the object of interest falling on the fovea centralis where the bulk of the cones reside. he visual perception of intensely blue objects is less distinct than the perception of objects of red and green. This reduced acuity is attributed to two effects. First, the blue cones are outside the fovea, where the close-packed cones give the greatest resolution. All of our most distinct vision comes from focusing the light on the fovea. Second, the refractive index for blue light is enough different from red and green that when they are in focus, the blue is slightly out of focus (chromatic aberration). While the visual acuity or visual resolution is much better with the cones, the rods are better motion sensors. Since the rods predominate in the peripheral vision, that peripheral vision is more light sensitive, enabling you to see dimmer objects in your peripheral vision. If you see a dim star in your peripheral vision, it may disappear when you look at it directly since you are then moving the image onto the cone-rich fovea region which is less light sensitive. You can detect motion better with your peripheral vision, since it is primarily rod vision. he light response of the rods peaks sharply in the blue; they respond very little to red light. This leads to some interesting phenomena: Red rose at twilight: In bright light, the color-sensitive cones are predominant and we see a brilliant red rose with somewhat more subdued green leaves. But at twilight, the less-sensitive cones begin to shut down for the night, and most of the vision comes from the rods. The rods pick up the green from the leaves much more strongly than the red from the petals, so the green leaves become brighter than the red petals! The ship captain has red instrument lights. Since the rods do not respond to red, the captain can gain full dark-adapted vision with the rods with which to watch for icebergs and other obstacles outside. It would be undesirable to examine anything with white light even for a moment, because the attainment of optimum night-vision may take up to a half-hour. Red lights do not spoil it. These phenomena arise from the nature of the rod-dominated dark-adapted vision, called scotopic vision.

What is the name of the instrument used to measure the thickness of the cornea and the depth of the anterior chamber? a. Pachymeter b. Lensmeter c. Keratometer d. Phoropter

A Corneal pachymetry. A pachymeter is a medical device used to measure the thickness of the eye 's cornea. It is used to perform corneal pachymetry prior to refractive surgery, for Keratoconus screening, LRI surgery and is useful in screening for patients suspected of developing glaucoma among other uses. ​

Small yellowish-white lesions located between the retinal pigment epithelium and Bruch's membrane are known as a. drusen. b. detachments. c. dermoids. d. dellen.

A Drusen are small yellow deposits of fatty proteins (lipids) that accumulate under the retina.Drusen are like tiny pebbles of debris that build up over time. There are two different types of drusen: soft and hard. "soft" drusen are large and cluster closer together "hard" drusen are smaller and more spread out A posterior epibulbar dermoid is a soft, yellow mass that molds to the shape of the eye and sometimes has small amounts of hair growing from it. These dermoids are usually found under the outer, upper eyelid and sometimes are visible only when lifting the eyelid or in certain gaze positions. Dellen are caused by interruptions of the tear film and local dehydration of the cornea. If untreated, they may lead to corneal perforation. We describe the case of a patient who developed corneal dellen 15 days after uneventful pterygium excision with CLAG with fibrin glue without the use of antimetabolites. Corneal Delle. Dellen are areas of corneal thinning secondary to stromal dehydration. They typically occur at the corneal limbus near areas of adjacent elevation. Stromal hydration can usually be restored with frequent ocular lubrication.

If a patient is unable to distinguish the largest letter on a Snellen chart, the assistant should a. determine if the patient can count fingers at a given distance. b. immediately assess for hand motion. c. darken the room and check for light perception. d. record "unable to assess" in the patient's chart.

A In patients who cannot identify the largest letter on the Snellen chart, test the patient's ability to identify the number of fingers displayed at a distance of 1 foot (1/3 meter) from each eye (with the other eye occluded).

Drugs that dilate the pupils are called' a. Mydriatics. b. miotics. c. beta-blockers. d. anesthetics

A Mydriatics are a type of medicine that make the pupil of the eye dilate (open up). Mydriatics also tend to relax the focusing muscles of the eye, which means that blurred vision is a common side effect. Miotics Agents causing contraction of the pupil of the eye. Some sources use the term miotics only for the parasympathomimetic (Parasympathomimetic Drugs Pilocarpine can be used to treat some disorders of the eye, such as glaucoma, which is characterized by elevated intraocular pressure. Pilocarpine is an effective treatment for glaucoma because one effect is to contract the ciliary muscle, which allows for fluid drainage of the eye.), but any drug used to induce miosis is included here. For example, pilocarpine. Beta blockers, also known as beta-adrenergic blocking agents, are medications that reduce blood pressure. Beta blockers work by blocking the effects of the hormone epinephrine, also known as adrenaline. Beta blockers cause the heart to beat more slowly and with less force, which lowers blood pressure. Beta blockers also help widen veins and arteries to improve blood flow. Timolol are an example of beta blockers Ophthalmic anesthetics are eye drops, gels, or ointments that contain a local anesthetic and can be administered directly into the eye. Ophthalmic anesthetics block the transmission of pain signals from the nerve endings of the eye to the brain, numbing the eye. Proparacaine drops.

The primary role and responsibility of ophthalmic medical personnel is the a. collection of data and the performance of clinical evaluations as authorized by the supervising licensed clinician. b. special testing, diagnosing, and the treatment of patients. c. measuring visual acuity and taking the patient's medical history. d. following of physician instructions no matter what the task.

A Ophthalmic medical personnel (OMPs) do tasks that the eye doctor can delegate to others. Mostly, they are information gatherers and facilitators. They do measurements and tests that provide the doctor with the information needed to arrive at a diagnosis and to prescribe treatment.

Soft contact lenses are susceptible to deposits of a. Proteins. b. enzymes. c. surfactants. d. leukocytes.

A Proteins Sometimes, despite the excellent care of the soft contact lenses, they are susceptible to penetration of proteins, which can denature the antigen and treaten eyes. Together with an increased amount of protein, the number of bacteria increases, and this may cause infection. Proteins are naturally discovered in your tears and can bind to your contacts. You might discover the protein deposits on your contacts as a thin haze on the lenses. While you might use a contact lens option to store your contacts, you should utilize a customized protein elimination option to remove protein deposits.

If the amount of light information transmitted to the brain from one eye differs from that of the other eye, the patient has a(n) a. afferent pupillary defect. b. Adie's pupil. c. tonic pupil. d. third nerve palsy.

A Relative Afferent Pupillary Defect (RAPD) is a condition in which pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve (only optic nerve disease occurs in front of the lateral geniculate body). Swinging flashlight test or Marcus Gunn test is one of the most basic eye exams that neurologists, ophthalmologists, optometrists and other physicians perform when visiting most of their patients. The doctor will ask the patient to look ahead then shines a penlight first toward one eye, then swing to the other, alternating quickly to observe patient's pupils' response to the light. In case if both pupils do not show a similar response to the light stimuli, shone in one eye at a time, the patient will be diagnosed with RAPD or Marcus Gunn pupils. off note if the condition is bilateral and symmetrical, there will not be a RAPD but bilateral APD. The results of this simple yet very important test help doctors in early diagnosis of many important eye related diseases such as optic neuropathy and multiple sclerosis Adie's pupil is a neurological disorder—a type of disease that affects the nervous system. The nervous system—made up of the brain, spinal cord, and nerves—controls many of our involuntary bodily functions. These are reflexive actions that happen automatically, without having to think about them—things like sweating, salivating, and sneezing. The nervous system also controls the pupil (small hole in the center of the iris) and its response to light. Normally, the pupil constricts (gets smaller) in brighter light to let less light in. In lower light, the pupil dilates (widens) to let more light in, so we can see better. With Adie's pupil, there is an abnormal pupillary response to light. In most cases, it affects only one eye. The affected pupil is usually larger than normal and does not constrict as it should in the presence of bright light. Tonic pupil: A pupillary abnormality characterized by a poor pupillary light reaction, reduced accommodation, iris sector palsies, an enhanced pupillary response to near effort that results in a prolonged, "tonic" constriction, and slow pupillary redilation. Causes of a third nerve palsy include: Poor blood supply to the third nerve caused by a combination of factors such as high blood pressure, diabetes, high... Direct pressure on the third nerve caused by swelling of neighbouring blood vessels known as an aneurysm, or tumours can... Head injuries can cause a third nerve palsy.

Retinoscopy is an example of what type of refractometry? a. Objective b. Subjective c. Immediate d. Latent

A Retinoscopy (also called skiascopy) is a technique to objectively determine the refractive error of the eye (farsighted, nearsighted, astigmatism) and the need for glasses. The test can be quick, easy, reliably accurate and requires minimal cooperation from the patient.

Retro illumination detects a. opacities or defects in the lens. b. irregularities of the eyelids or eyelashes. c. the palperal conjunctiva or sclera. d. adverse corneal effects from contact lenses.

A Retroillumination can be used to detect abnormalities in the iris. By shining a short, narrow beam directly through the pupil, abnormalities in the iris can be seen as areas of transillumination by light reflected off the retina. These so-called transillumination defects can result from a loss of pigmentation in the posterior iris and can be. **Diffuse Illumination Diffuse illumination explains when you use the open beam at 45°. This particular lighting technique is most effective for surveys of the lashes, lids, eye, surface vessels, sclera, caruncle, and media opacities. Sclerotic Scatter The sclerotic scatter uses a wide, tal beam aimed directly at the limbus. This technique scatters light throughout the cornea to display the patient's general pattern of opacities. Retroillumination In general, there are two common types of retroillumination lighting techniques you may use: Red Reflex Test involves a shorter beam of light being directed through the patient's pupil. The light is reflected off the retina to display iris illumination and reveal lens opacities. Iris Retroillumination involves light being reflected anteriorly off the deeper iris to allow an intuitive study of the guttata and corneal opacities.**

Probing of the tear duct may be useful treatment for patients with a. epiphora. b. epicanthus. c. exophoria. d. episcleritis.

A The meaning of EPIPHORA is a watering of the eyes due to excessive secretion of tears or to obstruction of the lacrimal passages. epicanthus a vertical fold of skin on either side of the nose, sometimes covering the inner canthus; a normal characteristic in persons of certain races, but anomalous in others. Exophoria is when one eye drifts outward during uneven visual stimulation or when viewing objects up close. It's most common when only one eye is covered. In such cases, the covered eye is the one that will drift outward. Exotropia is a condition in which the eyes drift outward and away from each other during times of equal visual stimulation. It tends to occur regularly. Episcleritis is an inflammatory condition affecting the episcleral tissue between the conjunctiva (the clear mucous membrane lining the inner eyelids and sclera) and the sclera (the white part of the eye) that occurs in the absence of an infection. The red appearance caused by this condition looks similar to conjunctivitis, but there is no discharge

The measurement used to determine the distance between the optical centers of spectacle lenses is the a. pupillary distance. b. axial length. c. vertex distance. d. refractive error.

A The measurement used to determine the distance between the optical centers of spectacle lenses is the pupillary distance The axial length (AL) is the distance between the anterior surface of the cornea and the fovea and usually measured by A-scan ultrasonography or optical coherence biometry. Vertex distance is the distance between the back surface of a corrective lens, i.e. glasses (spectacles) or contact lenses, and the front of the cornea. Refractive errors are vision problems that happen when the shape of the eye keeps you from focusing well.

If poor vision is simply due to refractive error, the acuity should improve with use of a(n) a. placido disc. b. pinhole disc. c. occluder over non-dominant eye. d. occluder over dominant eye.

B If pinhole acuity test is for to improve a patients poor visual acuity the patient a refractive error.

How many layers comprise the tear layer? a. 3 b. 4 c. 5 d. 6

A The tear film covers the normal ocular surface. It is generally considered to comprise the following 3 intertwined layers A superficial thin lipid layer (0.11 µm) - This layer is produced by the meibomian glands, and its principal function is to retard tear evaporation and to assist in uniform tear spreading A middle thick aqueous layer (7 µm) - This layer is produced by the main lacrimal glands (reflex tearing), as well as by the accessory lacrimal glands of Krause and Wolfring (basic tearing) an innermost hydrophilic mucin layer (0.02-0.05 µm) - This layer is produced by both the conjunctiva goblet cells and the ocular surface epithelium and associates itself with the ocular surface via its loose attachments to the glycocalyx of the microplicae of the epithelium; it is the hydrophilic quality of the mucin that allows the aqueous layer to spread over the corneal epithelium

In keratometry, if the power of the vertical meridian is greater than the power of the horizontal meridian, the patient has a. with-the-rule astigmatism. b. against-the-rule-astigmatism. c. keratoconus. d. nystagmus.

A With the Rule Astigmatism Whenever the vertical meridian of the cornea is steeper than the horizontal meridian of the cornea. The vertical meridian is considered to be between the 60th degree meridian and the 120th degree meridian. with the rule - steeper axis at 90 -44x90 and 43x80 -more common in younger patients and myopic eyes -when the greatest refractive power is within 30 of the vertical meridian (between 60 and 120 meridian) -correction with concave cylinder at horizontal axis ( 180 +/- 20) or convex at 90+/-20. -most common type against the rule -steeper axis at 180 -44x180 and 43x90 -more common in older pt ( cataract patients) -when the greatest refractive power is within 30 of horizontal meridian (between 30 and 150 meridians) -correction with concave cylinder at vertical axis ( 90+/- 20) or convex cyl at 180 +/- 20.

Consensual light reflex in the right eye results in a. right pupil constriction. b. right pupil dilation. c. left pupil constriction. d. left pupil dilation.

A consensual light reflex Ophthalmology The ability of both pupils to react to light which is tested by shining a beam of light in one eye, and assessing the response of the other eye, which normally constricts ​

Drugs that dilate the pupil without cycloplegia operate by stimulating which iris muscle? a. Dilator b. Sphincter c. Ciliary d. Rectus

A iris dilator muscle- The iris dilator muscle has fibers arranged radially from the sphincter to the ciliary border, receives sympathetic innervation, and functions to cause dilation of the pupil (mydriasis). The iris dilator muscle is a smooth muscle of the eye, running radially in the iris and therefore fit as a dilator. The pupillary dilator consists of a spoke like arrangement of modified contractile cells called myoepithelial cells. These cells are stimulated by the sympathetic nervous system. When stimulated, the cells contract, widening the pupil and allowing lighter to enter the eye. Phenylephrine is a sympathomimetic agent that is used clinically to dilate the iris without cycloplegia. Phenylephrine (2.5%) is used diagnostically for fundus examination, and 10% phenylephrine is used therapeutically to break posterior synechiae and pupillary block. The iris sphincter muscle is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil. The ciliary body is an inner eye structure that forms a semi-transparent ring on the outer surface of the choroid. It includes the ciliary muscle and the fingerlike ciliary processes. The ciliary processes are attached to the lens via zonular fibers. The lateral rectus is a muscle of the eye's orbit. The main function of this muscle is to pull the pupil away from the midline of the body.

What is the term for an area of complete or partial blindness in an otherwise normal visual field? a. Scotoma b. Synechiae c. Stye d. Stroma

A ​

Symptoms associated with a red, irritated, bloodshot eye are most likely due to a a. retinal detachment. b. cataract. c. conjunctivitis. d. open-angle glaucoma.

C

What common medium is used to culture microorganisms? a. plasma b. water c. agar d. stain

C

What is the proper technique to assist the visually impaired patient? a. Guide the visually impaired person to use the handrails on the wall b. Place their hand on your arm at the elbow c. Assisting the person into a wheelchair d. To take their hand

B If you are in a situation where you need to guide a blind or visually impaired person then make sure you guide them correctly. If you are asked to guide a blind or visually impaired person, let them take your arm, or ask them how they would prefer to be guided.

A slit lamp is used to examine the a. extraocular muscles. b. anterior chamber. c. optic tract. d. optic foramen.

B

After introduction to the patient, one of the first items that should be obtained as part of history taking is the a. medications and dosages that the patient is currently taking. b. chief complaint or reason for the patient's visit. c. patient's allergy history. d. patient's family medical history.

B

Axial length is provided by which measurement? a. Precorneal tear film to the posterior vitreous face b. Anterior corneal surface to the macula c. Anterior corneal surface to the optic disc d. Anterior pole to the posterior pole

B

Part of the rules for transposition is to change the axis of the cylinder by a. 45 degrees. b. 90 degrees. c. 180 degrees. d. 270 degrees.

B

What is the name of the condition in which the eye does not refract light equally in all directions? a. Emmetropia b. Astigmatism c. Amblyopia d. Esotropia

B

What is the term for drooping upper eyelids? a. Pterygium b. Ptosis c. Epicanthus d. Ectropion

B

What is the term for the tonometry technique that displaces a minimal amount of fluid? a. Indentation b. Applanation c. Elevation d. Fixation

B

Scotomas located immediately nasal or temporal to fixation are known as a. central. b. Paracentral c. arcuate. d. nasal step.

B **pericentral scotoma an arc-shaped defect, either continuous or not continuous with the blind spot, that arches into the nasal field and follows the course of retinal nerve fiber bundles arcuate scotoma** arcuate scotoma an arc-shaped defect of vision arising in an area near the blind spot and extending toward it. central scotoma an area of depressed vision corresponding with the fixation point and interfering with or abolishing central vision. When scotomata occur above and below the fixation point they meet in the nasal field and form a horizontal step-like defect. It is one of the signs of glaucoma.

How many dimensions are represented in a B-Scan image? a. 1 b. 2 c. 3 d. 4

B B-scan ultrasound refers to a two dimensional, cross-section brightness scan. It is typically used to evaluate posterior segment and orbital pathology, particularly when the ocular media are cloudy and a direct view is not possible.

In glare testing, how many controlled degrees of light does the BAT test deliver when the eye is viewing a Snellen target? a. 2 b. 3 c. 4 d. 5

B BAT (Brightness Acuity Test) gives the most accurate idea of a patient's visual disability. If a patient has a dense cataract it they will read worse when testing visual acuity with the BAT. Many insurances require that a patient have a visual acuity of 20 ⁄ 40 or 20 ⁄ 50 before they will cover the cataract surgery. The BAT helps achieve this goal. The patient s vision can be measured using low, medium or high light settings on the BAT instrument. The low lighting condition is similar to lighting in the workplace (driving, construction work, computer use, etc). The strong high light sources replicate oncoming headlights or a bright sky surrounding a visual target. If the patient s vision gets worse using the BAT, the patient is considered to have a glare disability. Usually this is caused by a cataract.

The optical centers of spectacles lenses MUST BE properly aligned in order to avoid what effect? a. Astigmatic b. Prismatic c. Presbyopic d. Myopic

B Ensuring proper frame alignment is an important part of the spectacle dispensing process. Ideally, for maximum optical benefit, patients should look through the optical centers of their lenses. Rays entering a lens at any point other than the optical center will be deviated as long as the lens has power, thus inducing prismatic effects.

What is a term for the state of pupillary constriction? a. Mydriasis b. Miosis c. Cycloplegia d. Anisocoria

B Miosis means excessive constriction (shrinking) of your pupil. In miosis, the diameter of the pupil is less than 2 millimeters (mm), or just over 1/16th of an inch. Miosis can occur in one or both eyes. When it affects only one eye, it's also called anisocoria. Another name for miosis is pinpoint pupil. There are many causes of miosis. It can be a symptom of certain brain and nervous system conditions. It can also be induced by many types of drugs and chemical agents. Opioids (including fentanyl, morphine, heroin, and methadone) can produce miosis Mydriasis is known to have a pupil diameter of about 4mm which is more than 33% of the iris. It may lead to an increase of Pupil from 4mm-9mm when it is adapted to the dark environment. This is the disorder in which pupil is dilated for a long time. In this condition, pupil fails to respond to light. excessive or prolonged dilatation of the pupil of the eye. Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation.[1] Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on nearby objects. This results in similar problems as those caused by presbyopia, in which the lens has lost elasticity and can also no longer focus on close-by objects. Cycloplegia with accompanying mydriasis (dilation of pupil) is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate. Tropicamide causes muscles in the eye to become relaxed. This dilates (widens) the pupil so that it does not react (narrow) when your doctor shines an examination light into your eye. Phenylephrine is a decongestant that shrinks blood vessels. Phenylephrine ophthalmic (for the eyes) is used to relieve eye redness, dryness, burning, and irritation caused by wind, sun, and other irritants. Prescription-strength phenylephrine ophthalmic is used to constrict blood vessels in the eye and to dilate (make bigger) the pupil for conditions such as glaucoma, before surgery, and before eye examinations. Anisocoria is unequal pupil size. The pupil is the black part in the center of the eye. It gets larger in dim light and smaller in bright light. Slight differences in pupil sizes are found in up to 1 in 5 healthy people. Most often, the diameter difference is less than 0.5 mm, but it can be up to 1 mm. Anisocoria Differential Diagnosis. This condition should be diagnosed in a proper manner, and for this, a number of tests needs to be performed. The differential diagnosis of this disease involves: Adie's Syndrome. Botulism. Alcohol intoxication. Cerebral Aneurysm. Brain tumor.

Near vision charts should be held how many inches from the eye? a. 10-12 b. 14-16 c. 18-20 d. 22-24

B One would need a 2.5D focus or 16 inches (40 cm) to 3.0D focus or 13 inches (33 cm). This would allow for a perfect, comfortable near read of a book, iPad, Nook or a similar item. close up vision test components are required at both 16 inches (near) and 32 inches (intermediate) positions in each eye separately. Near Vision and Intermediate vision are discussed together in the Legal Code.

Iridotomy is used to treat what type of condition? a. Open angle glaucoma b. Pupillary block c. Congenital glaucoma d. Pigmentary glaucoma

B Pupillary block is a type of angle closure glaucoma. As we know that the iris lies infront of the lens and usually there is no physical contact between the back surface of the iris and the anterior surface of the natural lens. The aqueous humor will flow from the posterior chamber of the eye through this space between the iris and the lens to the anterior chamber. This area is called the anterior chamber angle, or the angle. The cornea is the clear covering on the front of the eye that covers the iris, pupil, and angle. Anything that slows or blocks the flow of this fluid will cause pressure to build up in the eye. In open-angle glaucoma, the increase in pressure is often small and slow. Congenital glaucoma, also known as childhood glaucoma, is one of the several different types of glaucoma. Together, they are the second most common cause of blindness in the United States. This form of glaucoma is actually one of the less common types since glaucoma usually affects older adults. Surgery can treat this disease, and it typically has a high rate of success. Pigmentary glaucoma is an eye condition that occurs when the layer of the eye containing pigment, the iris, rubs against the lens, causing the release of pigment particles. These particles accumulate in the eye, preventing the fluid produced by the eye from draining.

What is the term for the 'bending of light'? a. Dispersion b. Refraction c. Emergence d. Incidence

B Refraction: the bending of light. . Refraction the bending of light. The bending of light as it passes from one medium to another is called refraction. The angle and wavelength at which the light enters a substance and the density of that substance determine how much the light is refracted. Dispersion - the action or process of distributing things or people over a wide area Emergence- the process of coming into view or becoming exposed after being concealed. Incidence- the occurrence, rate, or frequency of a disease, crime, or something else undesirable.

The Amsler grid is designed to evaluate visual field deficiencies in how many degrees of central vision? a. 10 b. 20 c. 45 d. 90

B The Amsler grid is a basic visual field test. This paper-based eye exam can easily be performed at home to monitor for disorders involving your central vision. The grid consists of 0.5 centimeters (cm) squares that form a larger square of 10 cm by 10 cm. This test evaluates 10 degrees of vision from a focal point which overall evaluates a visual acuity of 20 degrees.

What is the term for 'degerming' of the hands? a. Cleaning b. Scrubbing c. Sterilizing d. Septicizing

B The act of handwashing is an example of degerming, in which microbial numbers are significantly reduced by gently scrubbing living tissue, most commonly skin, with a mild chemical (e.g., soap) to avoid the transmission of pathogenic microbes. Sanitization refers to the reduction in the number of pathogens to a level deemed safe by public health guidelines. Degerming is the physical removal of microorganisms by using such things as soaps or detergents.

What is the name of the formula used to calculate induced prismatic effect caused by spectacle lenses whose optical centers have been decentered so they are not in line with the patient's visual axis? a. Snell's law b. Prentice's rule c. Prince rule d. Law of Reflection

B The formula used to calculate the amount of prism is called Prentice's Rule. The formula for Prentice's Rule is: Prism (diopters) = Power (diopters) X Decentration (centimeters). Prentice's Rule can be used to create prism in a lens. As opticians, we are trained to optimize a patient's vision. Prentice's Rule states: The power of the prism is equal to the power of the lens in diopters times the amount of decentration in millimeters divided by 10. dec = decentration or distance in mm away from the optical center of the lens. Prentice's rule: P = hD P = prism diopters of displacement, h = centimeters from the optical center, and D = diopters of power. For example, if a +4.00 D single vision lens is ordered to have the PD ground at 31mm, but instead was ground at 36mm (a difference of 5mm), one would use Prentice's rule to determine the amount of unwanted prism induced by the lens. The resulting formula: P = (0.5) × (4.00) With the formula P = .5 × 4.00 we can determine that the lens would create 2.00 D prism, which is greater than the tolerable value per the ANSI guidelines for a lens of this power. (Note: For the "h" value we need to change millimeters to centimeters; do this by moving the decimal point one space to the left, thus 5mm becomes 0.5cm) Snell's law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air. two quantities form a straight line on a graph, then a mathematical relationship can be written in y = m*x + b form. The indices of refraction (ni and nr) are given and the angle of incidence can be measured. AIR = N=0.00; WATER = N= 1.33; GLASS N=1.52

Measuring visual acuity with a potential acuity meter is useful for patients with a. glaucoma. b. cataracts. c. optic neuritis. d. Age-related Macular Degeneration.

B The potential acuity meter (PAM) is a device that is designed to project an eye chart directly onto the retina. This allows the examiner to test the visual acuity without interference from the cloudy lens. The main purpose of performing this test is to get an idea of the visual acuity that the patient can potentially achieve. Potential acuity pinhole (PAP) is a monocular test using a pinhole occluder to view a near target amidst bright illumination to predict visual status postoperatively. The patient is first dilated so that they are able to search for a subjectively clearer area that may be less obstructed from lenticular opacities.

What is the function of precorneal tear film? a. Reduce oxygen to the cornea b. Oxygenate the eye and provide a moist environment for the epithelium c. Increase friction and blinking d. Increase waste and cell debris

B The precorneal tear film has several important functions that are essential to the health of the eye. It: -maintains a moist environment on the surface of the eye, -preventing the epithelial cells from becoming dry and damaged lubricates the surface of the eye, facilitating the movement of the eyelids -maintains smooth refracting surface on the cornea, to ensure that the eye can see correctly -provides the cornea, which has no blood vessels, with the nutrients and oxygen necessary for its metabolism -contains enzymes (such as lysozyme), antibodies and phagocytic cells that destroy bacteria and prevent the growth of microcysts of the cornea -removes waste products from the cornea -eliminates foreign bodies from the surface of the eye by blinking -protects the cornea and conjunctiva against atmospheric and chemical irritants, as well as temperature changes.

The second step in preparing absorbable sutures before loading on a needle holder is a. cutting the suture in half. b. rinsing the suture. c. drying the suture. d. informing the physician that the suture is being prepared to load.

B The second step in preparing absorbable sutures before loading on a needle holder is Eye fatigue 20 feet or 6 meters dilator rinsing the suture

How many extraocular muscles move each eye? a. 4 b. 6 c. 9 d. 12

B There are the six extraocular muscles, which act to turn or rotate an eye about its vertical, horizontal, and antero-posterior axes: medial rectus(MR), lateral rectus(LR), superior rectus(SR), inferior rectus(IR), superior oblique(SO), and inferior oblique(IO).

A patient who has had an intraocular lens implantation is referred to as a. Aphakic b. Pseudophakic c. Phakic d. Lenticular

B a.

In visual assessment, an infant would be expected to reach for toys by the age of a. 2 - 4 months. b. 4 - 6 months. c. 6 - 8 months. d. 8 - 10 months.

B birth to 4 months- At birth, babies' vision is abuzz with all kinds of visual stimulation. While they may look intently at a highly contrasted target, babies have not yet developed the ability to easily tell the difference between two targets or move their eyes between the two images. Their primary focus is on objects 8 to 10 inches from their face or the distance to the parent's face.Eye-hand coordination begins to develop as the infant starts tracking moving objects with his or her eyes and reaching for them. By eight weeks, babies begin to more easily focus their eyes on the faces of a parent or other person near them.For the first two months of life, an infant's eyes are not well coordinated and may appear to wander or to be crossed. This is usually normal. However, if an eye appears to turn in or out constantly, an evaluation is warranted. Babies should begin to follow moving objects with their eyes and reach for things at around three months of age. 5-8 months during these months, control of eye movements and eye-body coordination skills continue to improve. Depth perception, which is the ability to judge if objects are nearer or farther away than other objects, is not present at birth. It is not until around the fifth month that the eyes are capable of working together to form a three-dimensional view of the world and begin to see in-depth. Although an infant's color vision is not as sensitive as an adult's, it is generally believed that babies have good color vision by 5 months of age. Most babies start crawling at about 8 months old, which helps further develop eye-hand-foot-body coordination. Early walkers who did minimal crawling may not learn to use their eyes together as well as babies who crawl a lot. 9 to 12 months At around 9 months of age, babies begin to pull themselves up to a standing position. By 10 months of age, a baby should be able to grasp objects with thumb and forefinger. By twelve months of age, most babies will be crawling and trying to walk. Parents should encourage crawling rather than early walking to help the child develop better eye-hand coordination. • Babies can now judge distances fairly well and throw things with precision. 1 to 2 years By 2 years of age, a child's eye-hand coordination and depth perception should be well developed. Children this age are highly interested in exploring their environment and in looking and listening. They recognize familiar objects and pictures in books and can scribble with crayons or pencils.

Checking the calibration of the applanation tonometer is done by a. only a qualified service technician. b. using a measured weight attached to the tonometer balancing arm at 0, 2, and 6. c. using a measured weight attached to the tonometer balancing arm at 0, 3, and 5. d. . having a second technician verify the IOP measurements on several patients to confirm tonometry accuracy.

B it is possible to check the calibration of the tonometer; this should be done every six months. Calibration is done at dial positions 0, 2, and 6 (equivalent to 0, 20, and 60 mmHg)

What is the name of the instrument that measures the power of spectacle lenses? a. Distometer b. Lensometer c. Tonometer d. Ophthalmometer

B lensometer measures vergence and prism power amongst other aspects of a lens. If a patient presents a pair of spectacles to you and does not know the Rx of the lenses, a lensometer will enable you to determine the sphere, cylinder, axis, and prism present in each lens. The Distometer is used to measure the distance between the apex of the cornea to the back surface of the lens. It is the perfect choice to better tailor digital progressive lenses to your patients. Remember to add 1mm to compensate for the thickness of the eyelid! Tonometry is a quick and simple test that checks the pressure inside your eyes. The results can help your doctor see if you're at risk for glaucoma. Glaucoma is a disease in which the nerve of the eye (the optic nerve) is gradually damaged over time, resulting in a loss of vision. This disease is often associated with increased eye pressure. The meaning of OPHTHALMOMETER is an instrument for measuring the eye; specifically : keratometer. Keratometer or ophthalmometer is used for: Evaluating degree of astigmatism . Fitting of eyeglasses and contact lenses. Analyzing patients having keratoconus. Determining intraocular lens power for patients suffering from cataracts.

The ophthalmologist instructs that a patient is to receive drops bid; the assistant should instruct the patient to take the drops a. once a day. b. twice a day. c. three times a day. d. four times a day.

B ophthalmic-dictionary_alphabetical_2011.pdf (uic.edu) QD- once a day BID- twice a day TID- three times a day QID- four times a day

A fibrovascular growth of the actually damaged conjunctiva that invades a portion of the cornea from the limbus is a a. Hyphema b. Pinguecula c. Pterygium d. Ptosis

C

A fluorescein angiogram is used for which of the following? a. Counting epithelial cells b. Measuring the eye's contrast sensitivity c. Viewing detail, such as blockages in fundus blood vessels d. Estimating the cornea's ability

C

1. The dioptric power of the cornea is determined by a. ultrasound readings. b. keratometer readings c. tonometer readings. d. tomography readings.

B the dioptric power of the cornea is determined Keratometer readings There are two parts to an eye and orbit ultrasound. The A-scan ultrasound takes measurements of your eye. The B-scan allows the doctor to see the structures in the back of your eye. The combined procedure (A and B scans) will take 15 to 30 minutes to complete. The A-scan measures the eye. Tonometer reading values are vital optometric measurements used to in the diagnosis, treatment, and management of glaucoma. Optical coherence tomography (OCT) is an optical analog of ultrasound imaging that uses low coherence interferometry to produce cross-sectional images of the retina. It captures optical scattering from the tissue to decode spatial details of tissue microstructures.

The iris, ciliary body, and choroid are collectively known as the a. vitrea. b. uvea. c. lacrima. d. palpebra.

B the pigmented layer of the eye, lying beneath the sclera and cornea, and comprising the iris, choroid, and ciliary body there is no such name as vitrea The vitreous is the gel-like fluid that fills your eye. It's full of tiny fibers that attach to your retina (the light-sensitive layer of tissue at the back of the eye). As you get older, the fibers of your vitreous pull away from the retina. This is called vitreous detachment. It usually happens after age 50. Lacrimal glands are the tear producing glands located above each eyeball. They continuously supply tear fluid that gets wiped across your eye surface each time you blink your eyelids. A common problem is the inflammation or swelling of the lacrimal gland. An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily.

What is the MOST commonly used technique to perform a B-scan? a. Slit lamp b. Handheld probe c. Computed Tomography (CT) (OCT) d. Magnetic Resonance Imaging (MRI)

B ​

The physiologic blind spot correlates with the optic a. chiasm. b. tract. c. nerve. d. zone.

C A particular blind spot known as the physiological blind spot, "blind point", or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through the optic disc. The optic chiasma, or optic chiasm, is the point in the brain where the optic nerves intersect. At this junction, approximately half of the fibers from each optic nerve cross over to the other side of the brain.. The optic nerve is mainly made up of the axons (nerve fibers) of the retinal ganglion cells from the retina. The optic disc or nerve head is the point where the axons from the retinal ganglion cells leave the eye. In fact, the optic zone of eyeglass lenses is the entire lens surface. The optic zone of contact lenses is only a portion of the lens, which is surrounded by peripheral fitting curves that do not affect vision.

Carbonic anhydrase inhibitors cause all of the following with the exception of a. numbness and tingling of the hands and feet. b. kidney stones. c. changing the color of the iris. d. drowsiness and fatigue.

C Answer is C changing the color of the iris. Everything else are side effects of the medications. Carbonic anhydrase inhibitors are a medication used in the management and treatment of glaucoma, idiopathic intracranial hypertension, altitude sickness, congestive heart failure, and epilepsy, among other diseases. Carbonic anhydrase inhibitors are considered part of the diuretic class of medications. Carbonic anhydrase inhibitor acetazolamide may be used to alkalize urine to solubilize uric acid and cystine stones. The adverse effects of CAIs that researchers and patients have reported include fatigue, vomiting, nausea, and abdominal pain. Stevens-Johnson syndrome is a rare side effect.[7] The alkalization of urine may promote the formation of calcium oxalate stones. The adverse effects of CAIs that researchers and patients have reported include fatigue, vomiting, nausea, and abdominal pain. Stevens-Johnson syndrome is a rare side effect.[7] The alkalization of urine may promote the formation of calcium oxalate stones. the side effects of carbonic anhydrase inhibitors More common Diarrhea. Increase in frequency of urination or amount of urine (rare with methazolamide) metallic taste in mouth. nausea or vomiting. numbness, tingling, or burning in hands, fingers, feet, toes, mouth, lips, tongue, or anus.

How are ultrasound biometric measurements obtained? a. The anterior lens spike should be lower than posterior lens spike. b. The patient must have good vision. c. The probe should be aligned along the visual axis of the eye d. The biometrist must press firmly on the globe.

C Biometry values can be obtained either by contact (applanation), immersion or optical methods. The contact/applanation technique is a widely used method which requires placing an ultrasound probe on the central cornea; this slightly indents the surface leading to various degrees of corneal compressions which may introduce errors into the values

The calibration of the Goldmann applanation tonometer should be checked at which settings? a. 0,1,2 b. 0,2,4 c. 0,2,6 d. 0,4,8

C Calibration of the Goldmann tonometer It is possible to check the calibration of the tonometer; this should be done every six months. Calibration is done at dial positions 0, 2, and 6 (equivalent to 0, 20, and 60 mmHg)

If a person can clearly see an object at 20 feet that can be seen at 60 feet by a person with no refractive error, their visual acuity is said to be a. 20/20 b. 20/40 c. 20/60 d. 20/80

C Having 20/60 vision means that you must be at 20 feet to see what a person with normal vision can see at 60 feet.

Corneal curvature measurement is vital to ensure that a contact lens a. touches the corneal surface. b. touches the conjunctival surface. c. rests on the cornea. d. rests on the tear film.

C It is important that the contact lenses fit properly, because a poorly fitting lens can cause further damage to the cornea. This might prevent the person from being able to wear contact lenses. Vital to your contact lens fitting is measuring the curvature of your cornea using a keratometry so that your eye doctor can select the optimal curvature and diameter dimensions for your new contact lenses. Keratometry evaluation is also helpful for detecting unknown corneal abnormalities like keratoconus, astigmatism or corneal scarring.

What is the name of the instrument that measures the curvature of the central part of the cornea? a. Tonometer b. Pachymeter c. Keratometer d. Lensmeter

C Keratometry is used to measure the curvature of the cornea. In some modern machines, keratometry tools are built into an all-in-one eye exam device. A keratometer can be used to determine the presence and extent of astigmatism. Tonometry is a quick and simple test that checks the pressure inside your eyes. The results can help your doctor see if you're at risk for glaucoma. Glaucoma is a disease in which the nerve of the eye (the optic nerve) is gradually damaged over time, resulting in a loss of vision. This disease is often associated with increased eye pressure. Corneal pachymetry. A pachymeter is a medical device used to measure the thickness of the eye 's cornea. It is used to perform corneal pachymetry prior to refractive surgery, for Keratoconus screening, LRI surgery and is useful in screening for patients suspected of developing glaucoma among other uses. Pachymetry can tell doctors if the cornea is swollen. Medical conditions such as Fuch's Dystrophy can increase fluid in the cornea and cause an increase in overall thickness. Even wearing contact lenses can sometimes cause significant corneal swelling. The lensometer helps orient appropriately and mark uncut lenses, verifying the power of single vision, bifocal and trifocal lenses, and checking the right mounting of eye lenses in spectacle frames. The device is used by the ophthalmologists or optometrists to evaluate certain parameters specified on the patient's prescription, such as cylinder, axis, sphere, add, and in some cases, prism. This instrument is often used to verify the accuracy of progressive lenses. It is also used to determine and mark the center of a lens and several other physical measurements that are essential for the proper functioning of the lens. At times, the lensmeter is used for a prior examination of a patient's eyes to match with the previous prescription that the patient was given.

The permeability of a contact lens is denoted by which value? a. RGP b. PMMA c. DK d. GPC

C The Dk value measures oxygen permeability, the Dk/t value measures oxygen transmissibility of a contact lens. Dk/t is calculated using the oxygen permeability (Dk) of the material and the thickness (t) of the contact lens. Usually, the Dk/t value refers to a lens with a certain power, therefore making it easier to compare lenses. Rigid gas permeable (RGP) lenses are hard contact lenses, which are also known as GP (gas permeable) lenses or oxygen permeable lenses. The first plastic contact lenses were produced in the 1930s. They consisted of a material called polymethyl methacrylate. RGPs are the most commonly prescribed lenses for keratoconus. Traditionally, these lenses were fit with small diameters, three-point touch and variable edge lifts to improve comfort. However, this type of fit often results in a low-riding lens, decentered inferiorly over the pupil which induces aberration. Pmma Contact Lenses. (Contact lens) A small plastic disc containing an optical correction that is worn directly on the cornea as a substitute for eyeglasses. Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic, often used as a light or shatter-resistant alternative to glass. Giant papillary conjunctivitis (GPC) is an allergic reaction that causes small round bumps called papillae, to develop on the inner lining of the upper eyelid. In many cases, GPC is caused by seasonal allergies or eczema, though it can also occur when your eyelids become irritated from constantly rubbing over a foreign object in your eye, such a contact lens or sutures.

Which surgical instrument is used to enlarge the punctum? a. Forceps b. Clamp c. Dilator d. Keratome

C The dilator is used to help enlarge the puncta and canaliculus for punctal or canalicular procedures such as probing, stenting, punctal plug placement, punctoplasty, or marsupialization of the canaliculus. These dilators serve a purpose identical to those of the Castroviejo dilators described above but are curved instead of straight. Ophthalmic Surgery Forceps are the most common instruments in eye surgery. Ophthalmic forceps include various types of eye surgery forceps: Scleral, Corneal, Tying, Iris, IOL, Fixation, Muscle, Conjunctiva, Prechopper, Capsulorhexis, Meibomian, etc. The following are three useful measurement which require keratometry Keratoconus - an eye disease that affects the curvature of the eye Preoperative cataract surgery Contact lens fitting With the rule vs against the rule. With-the-rule astigmatism means that the strongest axis is the vertical axis (90 degrees) in plus cylinder which is the same as 180 degrees minus cylinder. Against-the-rule astigmatism means that the strongest axis is the horizontal axis (180 degrees) in plus cylinder which is the same as 90 degrees minus cylinder. Example: Is the following prescription with-the-rule or against-the-rule. +1.00 +2.00 @90 Answer: With-the-rule, because the cylinder is positive and at 90 degrees. Is the following prescription with-the-rule or against-the-rule. +1.00 +2.00 @180 Answer: Against-the-rule, because the cylinder is positive and at 90 degrees Oblique astigmatism - the steepest curve lies in between 120 and 150 degrees and 30 and 60 degrees. Irregular astigmatism is when the axes of astigmatism are not 90 from each other. In other words they are not perpendicular. Regular astigmatism is he opposite of irregular astigmatism. Regular astigmatism means that the axes of astigmatism are 90 degrees apart. With-the-rule, against-the-rule, and oblique astigmatism are all regular astigmatisms.

How many nerves innervate the six extraocular muscles? a. 1 b. 2 c. 3 d. 4

C The extraocular muscles are innervated by lower motor neurons that form three cranial nerves: the abducens, the trochlear, and the oculomotor

On the back of a frame are a few figures such as 46 X 22. What do these numbers represent? a. Bridge and lens size b. Pupillary distance and segment height c. Lens and bridge size d. Segment height and pupillary distance

C The first number on your eyeglass frame is 55, which means your lens size is 55. And number 17 indicates the bridge size, that is to say, the fit distance between your nose is 17. The last number stands for the temple length, which indicates the fit over your ears is 150 Bridge Size is the distance between the two lenses in millimeters and typically ranges from 14 mm to 24mm. When measuring the bridge, you start and end at the innermost side of the lenses.

The thickest layer of the cornea is called the a. epithelium. b. endothelium. c. stroma. d. limbus.

C The stroma of the cornea (or substantia propria) is a fibrous, tough, unyielding, perfectly transparent and the thickest layer of the cornea of the eye. It is between Bowman's membrane anteriorly, and Descemet's membrane posteriorly. The cornea is the clear front surface of the eye. It lies directly in front of the iris and pupil, and it allows light to enter the eye. Viewed from the front of the eye, the cornea appears slightly wider than it is tall. This is because the sclera (the "white" of the eye) slightly overlaps the top and bottom of the anterior cornea. The horizontal diameter of the cornea typically measures about 12 millimeters (mm), and the vertical diameter is 11 mm, when viewed from the front. But if viewed from behind, the cornea appears circular, with a uniform diameter of approximately 11.7 mm. This makes the cornea about two-thirds the size of a dime. The center thickness of the average cornea is about 550 microns, or slightly more than half a millimeter. The cornea has five layers. From front to back, these layers are: 1. The corneal epithelium. This outer layer of the cornea is five to seven cells thick and measures about 50 microns — making it slightly less than 10 percent of the thickness of the entire cornea. Epithelial cells are constantly being produced and sloughed off in the tear layer of the surface of the eye. The turnover time for the entire corneal epithelium is about one week.Corneal epithelium. The corneal epithelium provides an optimal surface for the tear film to spread across the surface of the eye to keep it moist and healthy and to maintain clear, stable vision. 2. Bowman's layer. This is a very thin (8 to 14 microns) and dense fibrous sheet of connective tissue that forms the transition between the corneal epithelium and the underlying stroma. 3.The corneal stroma. This middle layer of the cornea is approximately 500 microns thick, or about 90 percent of the thickness of the overall cornea. It is composed of strands of connective tissue called collagen fibrils. These fibrils are uniform in size and are arranged parallel to the cornea surface in 200 to 300 flat bundles called lamellae that extend across the entire cornea. The regular arrangement and uniform spacing of these lamellae is what enables the cornea to be perfectly clear.Bowman's layer. The dense nature of Bowman's layer helps prevent corneal scratches from penetrating into the corneal stroma. Corneal abrasions that are limited to the outer epithelial layer generally heal without scarring; but scratches that penetrate Bowman's layer and the corneal stroma typically leave permanent scars that can affect vision. 4. Descemet's membrane. This very thin layer separates the stroma from the underlying endothelial layer of the cornea. Descemet's (pronounced "DESS-eh-mays") membrane gradually thickens throughout life — it's about 5 microns thick in children and 15 microns thick in older adults. 5.The corneal endothelium. This is the innermost layer of the cornea. The back of the endothelium is bathed in the clear aqueous humor that fills the space between the cornea and the iris and pupil. The corneal endothelium is only a single layer of cells thick and measures about 5 microns. Most of the endothelial cells are hexagonal (six-sided), but some may have five or seven sides. The regular arrangement of these cells is sometimes called the endothelial mosaic.Corneal endothelium. The single layer of cells that forms the endothelium maintains the fluid content within the cornea. Damage to the corneal endothelium can cause swelling (edema) that can affect vision and corneal health.

The concentration of a chemical in a pharmaceutical solution is also called the a. stability. b. sterility. c. Tonicity d. toxicity.

C Tonicity of any solution is associated with its solutions Osmolarity. Osmolarity is the overall concentration of all solutes solution within the solution. A solution concentration is a measure of the quantity of solute that has been dissolved in a given quantity of solvent or solution. One that contains a relatively high volume of dissolved solute is a concentrated solution. That that contains a relatively minimal volume of dissolved solute is a dilute solution. Tonicity is the 'effective osmolality' and is equal to the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane Hypotonicity is a property that can be addressed by the compounding pharmacist; hypertonicity can be addressed, if it is possible to decrease the concentration of some components of the formulation. Tonicity agents are added to injectable preparations to prevent osmotic shock at the site of injection upon administration, and thereby reduce local irritation. Typical excipients used for tonicity adjustment include saline, glycerin, mannitol, dextrose, and trehalose. Excipients are essential components of drug products. They are also potential toxicants. Examples of known excipient-induced toxicities include renal failure and death from diethylene glycol, osmotic diarrhea caused by ingested mannitol, hypersensitivity reactions from lanolin, and cardiotoxicity induced by propylene glycol. In general terms, sterility means the absence of any virus, bacteria, or other viable microorganisms. The same definition applies to pharmaceutical products, as they have to be free from any contamination to be sterile. Further, the sterile material should not facilitate the growth of any microorganisms on its surface. ​

The tendency of one eye to turn upwards is called a. esophoria. b. exophoria. c. hyperphoria. d. hypophoria.

C heterophoria in which there is permanent upward deviation of the visual axis of an eye in the absence of visual stimuli. Esophoria is an inward turn or deviation of the eye that only occurs some of the time. Eyes appear to work together normally in patients with esophoria, but if the fusion, or binocular vision, between the eyes is broken, an inward deviation can appear. Fusion can break between the eyes when the eyes focus on a near object and one eye turns inward more than necessary. "Phorias" and "tropias" of the eye occur as a result of poor eye alignment. However, phorias cause occasional misalignment when fusion is broken, and tropias usually present a constant deviation. Both phorias and tropias are often found in childhood. Both esophoria and esotropia cause the eye to drift inward, but the main difference is that esotropia is usually constantly present, and esophoria is not. Hypertropia is a form of vertical strabismus (eye turn), or misalignment of the eyes that occurs when one eye turns upward. When the eye turns downwards it called hypotropia.

A granulated inflammation of the eyelid that may be removed surgically if it does not subside is a: a. Xanthelasma b. Pterygium c. Stye d. Chalazion

D

A patient's prescription is -2.50 +1.00 X 175. What is the minus cylinder transposition? a. -2.50 -1.00 X 175 b. -2.50 -1.00 X 85 c. -1.50 - 1.00 X 175 d. -1.50 -1.00 X 85

D

According to OSHA regulations, what is the BEST way to comply with universal precautions? a. Put on a gown b. Put on gloves c. Use mask d. Wash your hands

D

How often should the surgeon's preference in instruments, sutures and preparation of the patient be updated? a. Occasionally b. Yearly c. Rarely d. Regularly

D

Intraocular pressure is measured with a(n) a. ophthalmometer. b. keratometer. c. lensmeter. d. tonometer.

D

Before sterilization, minor surgical instruments should be a. soaked in instrument milk. b. bleached. c. dusted. d. cleaned with soapy water.

D ​

Starting with plano in retinoscopy and using an appropriate working lens at 66 cm, a "with" reflex is MOST commonly observed in which refractive error? a. Exophoria b. Astigmatism c. Myopia d. Hyperopia

D "Against motion" = the light reflex is traveling in the opposite direction of the retinoscope beam. You need to add more minus to the prescription. "No motion" = the light reflex is neutral and is seen across the entire width of the pupil THE SETUP: Phoropter at plano, 20/400 letter with red/green filter, lights off. First Thing'S First: What Is Retinoscopy and Why Do We Do It? Definitions Short-Hand Info "With motion" = the light reflex is traveling in the same direction as the retinoscope beam. You need to add more plusto the prescription. "Against motion" = the light reflex is traveling in the opposite direction of the retinoscope beam. You need to add more minus to the prescription. (Helpful Hint: against motion (AM) = add minus (AM))

Ophthalmologists have a duty to ensure that each patient understands their a. eye anatomy. b. insurance coverage. c. ophthalmic instruments. d. treatment recommendations.

D "Rule 1. Competence. An ophthalmologist is a physician who is educated and trained to provide medical and surgical care of the eyes and related structures. An ophthalmologist should perform only those procedures in which the ophthalmologist is competent by virtue of specific training or experience or is assisted by one who is. An ophthalmologist must not misrepresent credentials, training, experience, ability or results." "Rule 2. Informed Consent. Informed consent is the process of shared decision-making between the ophthalmologist and the patient and must precede the performance of medical or surgical procedure. During the informed consent process, pertinent medical and surgical facts, and recommendations consistent with standard of care in medical/surgical practice must be presented in understandable terms to the patient or patient surrogate. Such information should include the indications, benefits, objectives, risks and possible complications of the procedure, alternatives to the procedure, and the potential consequences of no treatment. The operating ophthalmologist must personally confirm comprehension of this information with the patient or patient surrogate." Rule 3. Research and Innovation. Research is conducted to provide information on which to base diagnostic, prognostic or therapeutic decisions and/or to improve understanding of pathogenesis in circumstances in which insufficient information exists. Research and innovation must be approved by appropriate review mechanisms (Institutional Review Board; IRB) and must comply with all requirements of the approved study protocol to protect patients from being subjected to or potentially affected by inappropriate or fraudulent research. In emerging areas of ophthalmic treatment where recognized guidelines do not exist, the ophthalmologist should exercise especially careful judgment and take appropriate precautions to safeguard patient welfare. Appropriate informed consent for research and innovative procedures must recognize their special nature and ramifications. The ophthalmologist must demonstrate an understanding of the purpose and goals of the research and recognize and disclose financial and non-financial conflicts of interest. Commensurate with the level of his/her involvement, the investigator must accept personal accountability for patient safety and compliance with all legal and IRB-imposed requirements." "Rule 4: Other Opinions. The patient's request for additional opinions shall be respected. Consultation(s) shall be obtained if required by the condition." "Rule 9. Medical and Surgical Procedures. An ophthalmologist must not misrepresent the service that is performed or the charges made for that service. An ophthalmologist must not inappropriately alter the medical record." "Rule 10. Procedures and Materials. Ophthalmologists should order and/or utilize only those laboratory and surgical procedures, optical devices or pharmacological agents that are in the best interest of the patient. It is unethical to prescribe or provide unnecessary services and procedures or seek compensation for those services. It is equally unethical to withhold necessary services or procedures." "Rule 13. Communications to the Public. Communications to the public must be accurate. They must not convey false, untrue, deceptive, or misleading information through statements, testimonials, photographs, graphics and other means. They must not omit material information without which the communication would be deceptive. Communications must not appeal to an individual's anxiety in an excessive or unfair way, and they must not create unjustified expectations of results. If communications refer to benefits or other attributes of ophthalmic procedures that involve significant risks, realistic assessments of their safety and efficacy must also be included, as well as the availability of alternatives and, where necessary to avoid deception, descriptions and/or assessments about the benefits or other attributes of those alternatives. Communications must not misrepresent an ophthalmologist's credentials, training, experience or ability, and must not contain material claims of superiority that cannot be substantiated. If a communication results from payment by an ophthalmologist, this must be disclosed unless the nature, format or medium makes it apparent."

The MOST widely used method of visual field screening, requiring no special equipment, is a. Goldmann perimetry. b. the tangent screen. c. Amsler grid. d. confrontation testing.

D Confrontation visual field testing involves having the patient looking directly at your eye or nose and testing each quadrant in the patient's visual field by having them count the number of fingers that you are showing. This is a test of one eye at a time. Goldmann Visual Field Kinetic Perimetry Test. A patient's visual acuity can be impaired by ailments such as choroidal neovascular lesions. Perimetry is used to measure a patient's sensitivity to differential light within their visual field, by displaying objects to the patient and measuring their response to them. The Goldmann perimeter is a hollow white spherical bowl positioned a set distance in front of the patient. An examiner presents a test light of variable size and intensity. The light may move towards the center from the perimeter (kinetic perimetry), or it may remain in one location (static perimetry). //www.researchgate.net/publication/237684037_Understanding_Visual_Fields_Part_I_Goldmann_Perimetry#:~:text=There%20are%20two%20basic%20types%20of%20visual%20field,o%2C%20CA%29%20is%20a%20common%20example%20of%20static There are two basic types of visual field tests commonly used in the clinic. Depending on whether or not the stimulus moves, the test can be classified as static or kinetic. Goldmann perimetry is a common example of kinetic perimetry. The Humphrey Field Analyzer™ (Allergan-Humphrey, San Leandro, CA) is a common example of static perimetry. In fact, both perimeters have the capability of doing both static and kinetic tests, but in practice, they are used as described above. Perimeters can also be classified as manual or automated, depending on whether the stimulus is moved by hand as in the Goldmann, or if the stimulus location is changed by a computer, as in the Humphrey visual field (HVF). Kinetic perimetry involves the detection of moving targets and static perimetry involves the detection of a stationary target. Static testing in general is superior to kinetic perimetry in detecting slopes and scotomata (field defects), and tends to be more reliable and consistent, particularly for detecting glaucomatous visual field loss. A kinetic visual field test involves moving an object in and out of a patient's peripheral vision in order to find the edge of the patient's field of vision. A static field of vision test involves illuminating an object that doesn't move in the patient's field of vision in order to test the vision in this manner. The Tangent Screen is used to map a patient's peripheral vision by recording his/her response to test objects placed on the screen while the patient's stare is fixed on center target. The 1-meter black felt screen is mounted on a spring roller with mounting brackets. The tangent screen exam (Goldmann field exam) can be conducted in your eye doctor's office. You will be seated about 3 feet away from a computer screen. This screen will have a target in the center for you to focus on throughout the test. The computer will generate images on different areas of the screen. Without moving your eyes, you will tell your doctor when you are able to see objects in your side vision. Your doctor will be able to use the information collected to form a map of your visual field. This will help them determine if there are certain areas in your visual field that you are not able to see. The location of these areas can help your doctor diagnose the cause of the visual field problems. o determine if tangent visual fields gathered during assessment of superior visual field deficits caused by blepharoptosis and dermatochalasis offer good correlation to clinical exam in a time and cost efficient manner Tangent screen perimetry in the evaluation of visual field defects associated with ptosis and dermatochalasis (semanticscholar.org) Tangent visual fields are a rapid and inexpensive way to test for functional loss of superior visual field in patients with upper eyelid malposition. Our data revealed potential differences between tangent screen results and published results for automated or Goldmann visual field testing which warrants further studies. The Amsler grid is a simple square containing a grid pattern and a dot in the middle. This design, when used correctly, can show problem spots in your field of vision. For someone with AMD, an Amsler grid may appear to have wavy lines or blank spots.

What is the name of the drug that treats glaucoma by decreasing the production of aqueous humor? a. Cyclopentolate b. Tropicamide c. Latanoprost d. Timolol maleate

D Epinephrine drugs work both by decreasing the rate of aqueous humor production and increasing the outflow of fluid from the eye. This type of eye drop is used to treat glaucoma, and it is also used during eye surgery. Side effects include conjunctival deposits from the eye, blocked tear ducts, and heart palpitations. timolol is a beta-blocker that also reduces pressure inside the eye. Timolol ophthalmic (for the eyes) is used to treat open-angle glaucoma and other causes of high pressure inside the eye. This medication is used to treat high pressure inside the eye due to glaucoma (open angle-type) or other eye diseases (such as ocular hypertension). Lowering high pressure inside the eye helps to prevent blindness. This medication works by decreasing the amount of fluid within the eye. Timolol belongs to a class of drugs known as beta-blockers. What is the difference between timolol and timolol maleate? reaction findings between timolol hemihydrate and timo- lol maleate. The only known difference between these preparations is the maleate salt. 28 healthy subjects (26 completed) to timolol hemihydrate or timolol maleate given in both eyes twice daily, in a double masked fashion, for 1 week. Cyclopentolate is used to dilate (enlarge) the pupil. It is used before eye examinations (such as cycloplegic refraction or ophthalmoscopy).Why tropicamide is not used in children? Of the two shorter acting cycloplegics, tropicamide is reported to be less effective than cyclopentolate 11 15 16 17 and is considered by some to provide an unacceptable level of cycloplegia for refraction in children. Cyclopentolate provides cycloplegia for 12 to 24 hours, while tropicamide is expected to provide 4 to 10 hours of cycloplegia. Tropicamide is used to dilate (enlarge) the pupil so that the doctor can see into the back of your eye. It is used before eye examinations, such as cycloplegic refraction and examination of the fundus of the eye. Tropicamide may also be used before and after eye surgery Atropine cycloplegia results in a higher estimate of hyperopic refractive error than cyclopentolate in young children with moderate hyperopia. However, the mean SE difference is <0.50D.. Xalatan (latanoprost) is classified as an ophthalmic glaucoma agent and lowers pressure inside the eye by increasing the amount of fluid that drains from the eye.

Glaucoma primarily affects which ocular structure? a. Cornea b. Iris c. Zonules d. Optic Nerve

D Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. Glaucoma is one of the leading causes of blindness for people over the age of 60. It can occur at any age but is more common in older adults. ​

The results of keratometry can be expressed in a. cubic mm. b. mm Hg.q c. centimeters. d. diopters.

D Keratometry is considered an objective test, since it offers exact results that can not be manipulated by the patient. This test measures the refractive power of the cornea, which can be expressed as a radius of curvature (mm) or as an optical power ( Diopters). This last form throws the diopter s calculated according to keratometric index standards. ​

What is the name of the eyelid glands that secrete oil? a. Tear b. Lacrimal c. Palpebral d. Meibomian

D Meibomian glands are oil glands along the edge of the eyelids where the eyelashes are found. These glands make oil that is an important part of the eye's tears. The oily layer is the outside of the tear film that keeps tears from drying up too quickly. A number of eye problems can involve the meibomian glands. The tear glands (lacrimal glands), located above each eyeball, continuously supply tear fluid that's wiped across the surface of your eye each time you blink your eyelids. Excess fluid drains through the tear ducts into the nose. The tear film is a unique thin fluid layer of approximately 3μm thick and 3μl in volume that covers the outer mucosal surfaces of the eye. ... The most significant role of the lipid layer is in retarding evaporation of tears from the ocular surface. The aqueous/mucin layer forms the bulk of the tears.The lacrimal gland is located within the orbit above the lateral end of the eye. It continually releases fluid which cleanses and protects the eye's surface as it lubricates and moistens it. These lacrimal secretions are commonly known as tears. While you only have two lacrimal glands — one over each eye — you have 25 to 40 meibomian glands in your upper eyelid and 20 to 30 in your lower eyelid. Meibomian glands produce the oils that sit above the eyes' watery tear film (produced by the lacrimal glands), preventing it from evaporating too quickly. The palpebral are the upper and lower eyelids, which make up the shape of the eye. A line drawn from the inner corner to the outer corner determines the slant of the eye, or palpebral slant. Slanting and a fold of skin (epicanthal fold) are normal in people of Asian descent. ​

The source used to obtain the image in Optical Coherence Tomography is a. ultrasonic energy. b. visible white light c. visible red-green light. d. high resolution imaging.

D OCT exploits the short temporal coherence of a broadband light source, and enables high-resolution, non-invasive, in vivo imaging of microscopic structures in scattering tissues up to depths of approximately 2 mm, depending on the tissue type.

The site where half the nerve fibers from each eye cross over to the opposite side is called the optic a. disc. b. nerve. c. Tract d. chiasm.

D Optic chiasm provides a site for the crossing over or desiccation of optic nerve fibers so that contralateral half of the visual field is perceived and processed by the visual cortex. Optic chiasm is surrounded by the circle of Willis and derives its blood from the vessels forming this circle. At the optic chiasm, nerve fibers from half of each retina cross over to the opposite side of the brain. The fibers from the other half of the retina travel to the same side of the brain.

The exposed lens surface of an eyepiece should be dusted periodically with a a. wet tissue. b. dry sponge. c. soapy cloth. d. camel-hair brush.

D The exposed surfaces of the eyepiece optics (1) and the objective lens (2) should be cleaned using a soft optical dust brush. If, after being dusted, they still need additional cleaning, the lenses should then be wiped carefully with a lens cleaning cloth or with cotton swabs and lens cleaning solution.

The distance from the anterior surface of the eye to the back surface of the spectacle lens is the a. base curve. b. pupillary distance. c. lens distance. d. vertex distance.

D Vertex distance is the distance between the back surface of a corrective lens, i.e. glasses (spectacles) or contact lenses, and the front of the cornea. In optical theory it is said that the base curve is, "The curve from which all other curves are measured." In modern lens design we can think of the base curve as always being the front surface of the lens. In modern lens design that curve is always plus (+) and has a convex shape. **the higher the base curve number the "flatter" the curvature of the cornea. The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimeters (e.g., 28 mm, 50 mm, or 100 mm). ... Changing the focal length changes the angle of view.

The area between the two focal points of a spherocylindrical lens is called the Conoid of a. Schlemm. b. Streit. c. Schiotz. d. Sturm.

D Conoid of sturm is optically defined as, "A geometrical configuration of light rays emanating from a single point source and refracted by the sphero-cylindrical lens. The bundle of rays formed by an astigmatic optical system consisting of a primary focal line (called Sturm's line), a circle of least confusion and a secondary focal line (Sturm's line) perpendicular to the first. the conoid of sturm Schlemm's canal collects aqueous humor from the anterior chamber. It delivers it into the episcleral blood vessels via aqueous veins. streit is a brand of machine manufacture for mapping of the eye A Schiotz tonometer is an instrument for measuring the intraocular pressure (IOP). ​

The spherical equivalent of +2.00 + 5.00 X 180 is a. +7.00. b. +3.50. c. +4.50. d. +2.00.

c To calculate the spherical equivalent, you add half of the cylinder power to the sphere power. The first number is the sphere, the second number is the cyl, and the third number is the axis. Using Minus Cyl. To calculate the spherical equivalent for:'. +1.00 - 3.00 x 90. Ignore the third number, the axis. +2.00+5.00x180 +5.00 / 1/2= +2.50 +2.00+2.50= +4.50