COT study guide (GRO)

A lens formula of +2.00 -3.00 X 90 degrees has what power at 90 degrees and at 180 degrees? A. +2.00 and 4.00 B. +2.00 and -3.00 C. +540 and +3.00 0. -100 and +2.00

A. +2.00 and 4.00

Patient with a far point of 7.87" (25 cm) in front of the eye requires what spectacle lens power to correct their refractive error to emmetropia? A. -5.00 D B. -2.00 D C. +2.00 D D. + 5.00 D

A. -5.00 D The point reached where the image is most sharply focused on the retina Is called the far point.' The estimate of the extent of myopia Is done by calculating the reciprocal of the far point.

The inferior cul-de-sac capacity of a patient's eye pertaining to the Instilling of eye drops Is A. 1- 2 drops. 8. 3 - 4 drops. C. 5 - 6 drops. D. 7 - 8 drops.

A. 1- 2 drops. One to two drops ore bead of ointment is all that is needed. More than 1 drop Is a waste of solution because the total capacity of the cul-de-sac is a 1/6 of a drop.

A vertical muscle imbalance cannot be tolerated by a patient if it is over A. 1.00 D. B. 1.50 D. C. 1.75 D. D. 2.00 D.

A. 1.00 D. A vertical muscle Imbalance of over 1.00 diopter cannot be tolerated by the patient

Calibration of the Goldmann applanation tonometer should be checked approximately every A. 2 months with regular use. B. 3 months with regular use. C. 8 months with regular use. D. 12 months with regular use

A. 2 months with regular use. Calibration of the applanation tonometer important and it should be checked approximately every 2 months or sooner with regular use.

In ordinary room light, the diameter of the normal adult pupil is A. 3 - 5 mm. B. 6 - 9 mm. C. 10 - 13 mm. D. 14-17 mm

A. 3 - 5 mm. Pupil size in adults is about 3 mm. The normal pupillary diameter is about 3 - 4 mm. The diameter of a normal adult pupil Is between 3 - 5 mm.

If the K value of a patient being tit for RGP contact lenses is recorded as 43.50/44.50, the BC of CL on K would be which of the following? A. 43.50 B. 44.00 C. 44.50 D. 45.00

A. 43.50

Threshold is a relative term and represents the level where a stimulus can be seen what percentage of time? A. 50% B. 60% C. 70% D. 80%

A. 50% Threshold is a relative term and represents where a stimulus can be seen 50% of the time.

A 79-year old female is taking medication for open angle glaucoma. She has a syncopal episode and is found to have a pulse rate of 36 beats per minute. Which of the following glaucoma medications Is most likely the cause? A. Acetazolamide B. Mannitol C. Piiocrapine D. Timolol

A. Acetazolamide

Which procedure is MOST likely to give a falsely elevated intraocular pressure reading? A. Air puff tonometry B. Applanation tonometry C. Digital pneumotonoraphy D. Indentation tonometry

A. Air puff tonometry Air puff tonometry is moderately accurate as a screening device it becomes increasingly less accurate as intraocular pressure increases beyond the normal upper limit. Romer to name airb.sawaL The noncontact (air-puff) tonometer is not as accurate as applanation tonometry. The air puff tonometer tends to err slightly on the high aide.

Which type of fens eliminates distortion found at the edge of the field In hand and stand readers? A. Aspheric lens B. Convex lens C. Keeler lens D. Hruby lens

A. Aspheric lens

Which of the following drugs has the longest duration of action? A. Atropine B. Cydopentolate C. Homatropine D. Scopolamine

A. Atropine

When the reflex Is neutralized by lenses the light appears to A. Fill the pupil B. move with the intercept. C. disappear. D. move against the Intercept.

A. Fill the pupil

Unequal semi-circles during applanation tonometry are caused by A. Incorrect centering of the tonometer head. B. too much fluorescein. C. too little fluorescein or evaporation of fluorescein. D. incorrectly positioning the patient.

A. Incorrect centering of the tonometer head.

What is the primary purpose of epinephrine use with glaucoma? A. Increase aqueous outflow B. Increase aqueous production C. Decrease aqueous outflow D. Decrease aqueous production

A. Increase aqueous outflow

Homonymous congruous visual field defects with macular sparing are located in what part of the visual pathway? A. Occipital cortex B. Optic chiasm C. Optic nerve D. Optic radiation

A. Occipital cortex Any lesion affecting an area interior to the calcarine fissure will produce congruous homonymous hemianopsia that spares central vision.

Latrogenic or self-induced pupil constriction can be caused by which drug? A. Phaspholine Iodide B. Cyclopentolate C. Scopolamine D. Thnoloi

A. Phaspholine Iodide. Decreased cholinesterase activity allows naturally released acetylcholine to stay longer in the synaptic space and continue parasympathetic action.

If a patient's visual acuity measures 20/70 with correction and pinholes to 20/25, which of the following is MOST likely? A. The patient needs distance correction. B. The patient is malingering. C. The patient should be dilated and examined for retinopathy. D. The patient has cataracts.

A. The patient needs distance correction. Improved vision through a pinhole indicates a refractive error, a defect In the power of an eye's multiple lens system that can be corrected by eyeglasses or contact lenses. If the patient needs glasses or their glasses are unavailable, the corrected acuity can be estimated by testing vision through a pinhole. The pinhole disc thus serves to differentiate visual loss caused by refractive errors from poor vision resulting from disease of the eye.

Open-angle glaucoma Is primarily caused by abnormalities in which structure? A. Trabecular meshwork B. Posterior chamber C. Ciliary processes D. Iris

A. Trabecular meshwork In open-angle glaucoma (the most common type) the diameter of the openings of the trabecular meshwork becomes narrowed, thereby Increasing the resistance to fluid flow.

If the working distance of 2/3m (66c) without a +1.50 working lens Is in place, the reflex in the A. accommodating hyperope would be "with" motion. B. myope of -2.00 would be neutral. C. emmetrope would be "against" motion. D. unaccommodated hyperope of +0.75 would be neutral.

A. accommodating hyperope would be "with" motion.

The Goldman applanation tonometer head and chin rests are best cleaned by wiping the surfaces with A. alcohol. B. bleach. C. acetone. D. water.

A. alcohol.

Antihistamines play an essential role in the management of A. allergic conjunctivitis. B. glaucoma. C. retinoblastoma. D. uveitis.

A. allergic conjunctivitis.

Reduced visual acuity without any detectable organic cause is referred to as A. amblyopia. B. strabismus. C. anisometropia. D. suppression.

A. amblyopia. Amblyopia is a term for a loss of vision in one or both eyes in which no organic pathologic condition is seen in the eyes or optic nerves.

Instruments that are slim-handled with bowl-shaped ends are A. curets. B. clamps. C. needle holders. D. scalpels.

A. curets.

Vertex distance refers to the A. distance between the two optical centers of the spectacle lens. B. distance from the cornea to the back surface of the lens. C. difference between the distance versus near PD. D. the pantoscopic angle of the frame.

A. distance between the two optical centers of the spectacle lens. Vertex distance is that between the corneal surface and the eyeglasses' correction.

The method used to permanently remove lashes from the eye lid margin is A. electrolysis. B. iridotomy. C. myectomy. D. vitrectomy.

A. electrolysis. Electrolysis is a method to permanently remove lashes from the eye lid margin.

The code of rules and customs by which physicians are bound are referred to as medical A. ethics. B. decency. C. morality. D. standards.

A. ethics.

Miotics (parasympathomimetic agents) are used as a topical therapy for A. glaucoma. B. macular degeneration. C. conjunctivitis. D. amblyopia.

A. glaucoma.

Intraocular pressure is highest during the A. morning. B. afternoon. C. early evening. D. late evening.

A. morning. The pressure normally varies in an eye at different times of day. It is highest in most people in the morning.

The optic chiasm is the crossing point for the retinal nerve fibers and the A. optic nerves forming the optic tracts. B. nasal retina to each eye. C. temporal retina to each eye. D. retinal nerve fibers that cause pupillary

A. optic nerves forming the optic tracts.

Cycloplegic refraction Is performed to A. prevent the accommodative effort required to compensate for hyperopia. B. reveal the acceptability of a particular correction. C. only detect minimal refractive error. D. reveal full correction of hyperopic error.

A. prevent the accommodative effort required to compensate for hyperopia. Cycloplegia paralyzes accommodation allowing the full refractive error to be more easily determined, especially In hyperopia.

Globe rupture following blunt force Injury should always be suspected when A. retinal detachment, vitreous hemorrhages, and a rupture of the choroid are present. B. diplopia Is a major symptom. C. lid ecctrymosis is a major finding. D. proptosls Is present

A. retinal detachment, vitreous hemorrhages, and a rupture of the choroid are present. Similar abnormalities, as well as hemorrhagic chernosis, softening and possible collapse of the eye, and vitreous hemorrhage, occur in sclera laceration, which should be particularly suspected if there is deep eyelid laceration. Initially, the effects of a blow to the eye can be disastrous because perforations of the globe, with prolapse of the intraccular contents, vitreous hemorrhage, retinal detachment and the rupture of the choroid may occur as an Immediate complication.

In a patient with dry eyes, the doctor may ask you to conduct a Schirmer's test. The test should be performed with A. strips avoiding corneal contact. S. use of a mydriatic. C. use of a cycloplegic. D. the patient sedated.

A. strips avoiding corneal contact. In this test a standardized filter paper is inserted In the unanesthetized lower fornix of each eye at the junction of the middle and nasal third of the lower lid margin.

The axes of the Jackson Cross Cylinder are marked as plus cylinder - A. white, minus cylinder - red. B. red, minus cylinder - white. C. blue, minus cylinder-yellow. D. yellow, minus cylinder - blue.

A. white, minus cylinder - red. Red dot is minus and the white dot is plus.

A physician writes the following prescription: Atropine 1% gtts I OS q. hs x 5d. The prescription is A.1 drop Atropine 1% solution by mouth before bed for live days. B.1 drop Atropine 1% solution In the left eye every night before bed for five days. C.1 mm Atropine 1% ointment in the left eye every night before bed for five days. D. 1 mm Atropine 1% ointment In the left eye every hour for five hours.

B. 1 drop Atropine 1% solution In the left eye every night before bed for five days.

How many dimensions are represented In a B-scan Image? A. 1 B. 2 C. 3 D. 4

B. 2 Two dimensional 8-scans display multiple A-scans as dots rather than spikes. The B-scan display represents a two-dimensional cross section of the globe.

A normal blink rate is typically every A. 1- 2 seconds. B. 3 - 4 seconds. C. 5 - 6 seconds. D. 7 - 8 seconds.

B. 3 - 4 seconds. Most people blink 15 times per minute.

The astigmatic clock has black lines intersecting at a common point with the and separated by A. 20-degree or 5-degree intervals. B. 30-degree or 10-degree intervals. C. 40-degree or 15-degree intervals. D. 50-degree or 20-degree intervals.

B. 30-degree or 10-degree intervals.

A +12 D lens Is designated as a magnifier of which power? A. Ix B. 3x C. 4x D. 5x

B. 3x The magnification of a lens in X power multiplied by 4 equals the approximate dioptric power of the lens. A 5X lens X 4 = +20D

What is the metric equivalent of 20/40 visual acuity? A. 6/10 B. 6/12 C. 6/15 D. 6/20

B. 6/12

Which of the following should NOT be used to clean a phoropter? A. Non-static cloth B. Alcohol C. Water D. Glass cleaner

B. Alcohol Alcohol should not be used on any part of the phoropter.

The visual field defect In which there is a complete type of nerve fiber bundle defect emanating from the blind spot, arching over central fixation, and ending on the horizontal line is a A. absolute scotoma. B. Bjerrum scotoma. C. contraction. D. relative scotoma.

B. Bjerrum scotoma.

The layers of the cornea are as follows: A. Corneal epithelium, Stroma, Bowman's membrane. Descemet's membrane, and the Corneal endothelium B. Corneal epithelium, Bowman's membrane, Stroma, Descemet's membrane, and the Corneal edothelium C. Corneal epithelium, Bowman's membrane, Descemet's membrane, Corneal edothelium, and the Stroma D. Corneal endothelium, Bowman's membrane, Stroma. Descemet's membrane, and the corneal epithelium

B. Corneal epithelium, Bowman's membrane, Stroma, Descemet's membrane, and the Corneal edothelium

How do carbonic anhydrase inhibitors affect the production of aqueous humor? A. Increase production B. Decrease production C. No effect on production D. Maintain normal production

B. Decrease production

In order to test the function of the superior oblique muscle, the eye is directed into which field of gaze? A. Down and lateral B. Down and medial C. Straight ahead D. Up and lateral

B. Down and medial

Tear duct irrigation may be Indicated for which of the following conditions? A. Xanthelasma B. Epiphora C. Entropion D. Hypotony

B. Epiphora Epiphoria (overflow of tears onto the face due to the lack or substantially reduced drainage of tears through the nasolacrimal system). Lacrimal surgery may be beneficial.

The actual weight of the instrument can produce measurement error with which type of tonometer? A. Goldmann B. Indentation C. Non-contact D. Perkins

B. Indentation A major disadvantage of the Schiotz tonometer is that weight reading can be affected by either the improper manipulation of the instrument or the rigidity (distensibility) of the sclera.

What is NOT Important when documenting the history of an ocular injury? A. How the injury occurred B. Presence of others when the injury occurred C. The time the Injury occurred D. Treatment received since the Injury occurred

B. Presence of others when the injury occurred. It is essential to establish as precisely as possible the circumstances and mechanism of injury and any pre-existing ophthalmic abnormality.

Which of these ocular conditions is LEAST likely to render Goldmann tonometry inaccurate? A. Keratoconus B. Retinitis pigmentosa C. Pterygia D. Corneal scars

B. Retinitis pigmentosa Corneal irregularities such as scars, pterygia, grafts or keratotomies alter the smooth surface of the epithelium, often rendering Goldmann tonometry inaccurate. Corneal distortion such as seen with scarring or high astigmatism creates difficulty in obtaining reliable end-point measurements.

The variance in corneal curvature measured with a keratometer reveals the A. radius of corneal curvature. B. amount of corneal astigmatism. C. cylinder axis. D. steepest K.

B. amount of corneal astigmatism. The difference between the two meridians indicates the amount of compel astigmatism.

Epidemic adenovirus keratocorgunctivItts is transmitted through A. linear to eye. B. applanation tonometry. C. fluorescein solutions. D. kissing.

B. applanation tonometry.

Common anesthetic agents such as proparacaine, teracaine, and lidocaine are administered A. as inhalants. B. as eyedrops. C. orally. D. intravenously.

B. as eyedrops.

Cytology is the study of A. microbial organisms. B. cell types. C. gram and Glemsa smears. D. adenoviruses.

B. cell types.

An obstruction of the melbomian gland generally causes A. pterygiums. B. chalazions. C. ptosis. D. entroplon.

B. chalazions.

The purpose of the swinging flashlight test is to compare the A. consensual response stimulated eye and the direct response in the other eye. B. direct response stimulated eye and the consensual response In the other eye. C. direct response and the near response in the same eye. D. direct response at 20 feet (6 meters) in the same eye.

B. direct response stimulated eye and the consensual response In the other eye. The consensual response to light Is the reaction seen simultaneously in the non-illuminated eye. The consensual response Is the normal simultaneous constriction of the opposite non-illumlnated pupil. The normal direct light response causes constriction of the pupil on that side.

Normal 'against-the-rule" astigmatism on a topographic map of the cornea will display as a A. vertical bow-tie shape. B. horizontal bow-tie shape. C. pellucid image. D. flattening of the cornea toward the periphery.

B. horizontal bow-tie shape.

The term for the education of the patient. asking for their participation in the decision making process is A. client confidentiality. B. informed consent. C. patient privacy. D. patient responsibility.

B. informed consent. Informed consent is a process documented in the patient's health record, wherein the physician or a trained delegate (e.g., ophthalmic assistant) educates the patient and asks for his or her participation in the decision-making process.

Dynamic visual acuity refers to A. acuity measured in a controlled medical office setting. B. kinetic or moving vision. C. contract sensitivity acuity. D. pinhole acuity.

B. kinetic or moving vision.

A patient who is unable to abduct the left eye may have a weakness of the A. right medial rectus muscle. B. left lateral rectos muscle. C. left medial rectus muscle. D. right lateral rectus muscle.

B. left lateral rectos muscle.

The type of drug that stimulates the effect of acelylocholine is a A. parasympatholytic. B. parasympathomimetic. C. sympetholytic. D. sympathomimetic.

B. parasympathomimetic.

In evaluating a fluorescein angiogram, cystoid macular edema is represented by A. dye leakage In the macula. B. punctate areas of hyperfluoresceln. C. block of the choroid. D. scattered hemorrhages.

B. punctate areas of hyperfluoresceln. The patient has decreased vision as a result of macular edema from vessel leakage.

The spherical equivalent is calculated by A. algebraically adding the sphere and cylinder power. B. reducing the cylinder by half and algebraically adding that reduction to the sphere. C. transposing the minus cylinder to plus. D. subtracting the retinoscopy working distance from the sphere power.

B. reducing the cylinder by half and algebraically adding that reduction to the sphere.

When performing refractometry, the Jackson cross cylinder Is used to A. determine the amount of raced astigmatism. B. refine the cylinder power and axis. C. refine the spherical power. D. determine the endpoint of the refraction.

B. refine the cylinder power and axis. The cross-cylinder allows rapid small changes in the axis and power of cylindrical correction. The cross cylinder Is relining instrument that determines the exact axis of astigmatic error and the exact power of the cylinder.

If the ophthalmologist prescribes a drop for a patient to use 4 times a day In their left eye, which of the following would be correct? A. 1 gtt tid OD qid B. 1 gtt tid OS qid C. 1 gtt qid OS qid D. 1 gtt qid OD qid

C. 1 gtt qid OS qid

The lines of optotypes are what size in comparison to the entire optotype? A.1/2 B.1/4 C.1/5 D. 1/6

C. 1/5

What is the velocity of sound in aqueous? A. 1641 mis B. 1550 m/s C. 1532 m/s D. 980 m/s

C. 1532 m/s

A visual acuity of 20/200 obtained at a distance of 4 feet should be recorded as A. J10. B. 6/60. C. 4/200. D. < 20/200.

C. 4/200. The numerator is the distance at which the patient tested, usually 29 feet. The denominator is marked at which the test object subtends an angle of five minutes of arc on the retina. Visual acuity is scored as a fraction (e.g. 20/40). The first number represents the testing distance between the chart and the patient, and the second number represents the smallest row of letters that the patient's eye can read. 4/200 indicates that the patient was 4 feet from the 20/200 letter.

What is an average corneal curvature measurement? A. 42 D B. 43 D C. 44 D D. 45 D

C. 44 D

The normal visual field is determined by the size of the test object employed and the distance at which the test was made. With a 3mm white target on the perimeter of a 330-degree radius, the average peripheral limit is approximately A. 75 degrees outward, 55 degrees downward, 40 degrees inward and 40 degrees upward. B. 85 degrees outward, 65 degrees downward, 50 degrees inward and 50 degrees upward. C. 95 degrees outward, 75 degrees downward, 60 degrees inward and 80 degrees upward. D. 105 degrees outward, 85 degrees downward, 70 degrees inward and 40 degrees upward.

C. 95 degrees outward, 75 degrees downward, 60 degrees inward and 80 degrees upward. The normal visual field is determined by the size of the test object employed and the distance at which the test was made. With a 3mm white target on the perimeter of a 330.degree radius, the average peripheral limit Is approximately 95 degrees outward, 75 degrees downward, 60 degrees Inward and 60 degrees upward.

What Is the MOST significant advantage of the applanation tonometer compared with the Indentation tonometer? A. Applanation is a more modern technique. B. Applanation causes less patient discomfort. C. Applanation is more accurate because a negligible amount of aqueous is displaced from the anterior chamber. D. Applanation instruments are more cost effective.

C. Applanation is more accurate because a negligible amount of aqueous is displaced from the anterior chamber. Applanation tonometry assesses intraocular pressure by a sophisticated, highly accurate, reliable method. The Goldmann applanation tonometers give a reliable measurement of intraocular pressure to within +/-0.5 mmHg.

Sudden loss of vision in one eye MOST likely indicates A. amblyopia. B. cataract C. central retinal artery occlusion. D. retinitis pigmentosa.

C. Central Retinal Artery Occlusion (CRAO) An acute blockage leads to Immediate catastrophic loss of vision In the involved eye. Refer to pages 1913-199, Source B. Retinal vein occlusion is a common and easily diagnosed retinal vascular disorder with potentially blinding complications. Central retinal artery occlusion Is the most urgent in terms of time. If this artery remains occluded for 1 hour or more, the involved eye will go totally blind.

Which one of the following ocular conditions will LEAST likely present in a patient's family history? A. iteratoconus B. Nystagmus C. Conjunctivitis D. Retinitls pigmentosa

C. Conjunctivitis All major eye problems In family members are relevant. The family history is pertinent for ocular disorders, such as strabismus, amblyopia, glaucoma, or cataracts, and retinal problems. The presence or absence of such familial diseases such as myopia, strabismus, and glaucoma should be asked about

What fundamental Issue enhances patient trust and partnership while aiding patients to understand their disease? A. Informed consent B. Cultural beliefs C. Honest patient communication D. Proper documentation

C. Honest patient communication Truth telling enhances trust end partnership and also aids the patient in understanding their disease.

Which type of lens power is used to neutralize against motion? A. Plano B. Plus C. Minus D. Polaroid

C. Minus

A difference In pupil size is referred to as A. Adie's Syndrome. B. Marcus Gunn pupil. C. anisocoria. D. hippus.

C. anisocoria. Ten percent of the population has anisocoria (difference In pupil size).

A contact lens fit 'steeper than K' is defined as a A. minus tear lens. B. corneal radius of 7.6 mm and the contact lens radius could be 7.8 mm. C. corneal measurement of 44.00 diopters and the contact lens curvature could be 44.50 diopters. D. base curve of the contact lens which Is the same radius of the curvature of the anterior cornea.

C. corneal measurement of 44.00 diopters and the contact lens curvature could be 44.50 diopters. To steepen the fit of a contact lens, increase the dioptric curve (decrease the millimeters of radius of curve).

The MOST common form of color vision defect Is A. absence of blue color recognition. B. complete color blindness. C. deficient red-green color recognition. D. deficient yellow-blue color recognition.

C. deficient red-green color recognition. A deficiency of red-sensitive cones (protanomaly) results In poor red-green discrimination and so the red end of the spectrum appears dimmer than normal. The most common congenital color vision defect red-green color deficiency, is a form of dichromacy, with only two out of three cone opsins functioning normally.

The term for "right gaze" is A. supraversion. B. infraversion. C. dextroversion. D. levoversion.

C. dextroversion.

A "scissor reflex" may occur during retinoscopy and is associated with A. cataracts. B. Fuch's dystrophy. C. keratoconus. D. narrow angle glaucoma.

C. keratoconus. There is an irregular or scissor reflex on retinoscopy and a distorted corneal reflection with Placido's disk or the keratoscope even early in the disease.

The difference between the farthest and nearest distance at which a patient Is able to see clearly is known as A. convergence amplitude. B. Panum's fuslonal space. C. range of accommodation. D. the add.

C. range of accommodation. Range of accommodation is the distance between the far point and the near point of accommodation through which the eye can see clearly expressed in meters. The range of accommodation is the distance In which an object can be carded toward an eye and be kept in focus.

The electroretinogram tests the function of A. cones. B. rods. C. rods and cones. D. RPE cells.

C. rods and cones.

A sample of discharge or tissue cells obtained by scraping is a A. smudge. B. fragment C. smear D. specimen.

C. smear

Corneal astigmatism is BEST corrected by A. extended wear spherical soft contact lenses. B. hydrogel spherical soft contact lenses. C. spherical RGP or soft lenses. D. thin cut PMMA lenses.

C. spherical RGP or soft lenses. Corneal astigmatism can be corrected by both rigid and soft with lenses. Rigid lenses overcome corneal astigmatism. Including irregular astigmatism by modifying their anterior surface of the eye into a truly spherical shape.

Pachymetry measures corneal A. steepness. B. curvature. C. thickness. D. diameter.

C. thickness. The optical pachymeter is available in two different models: one for measuring the thickness of the cornea and one for estimating the depth of the anterior chamber.

When performing A-scan biometry, correct alignment of the probe is BEST determined by A. tissue spikes that gradually Increase In height B. an axial length measurement between 22 mm and 25 mm. C. tissue spikes that are equally tall and sharp. D. an axial length measurement that Is almost equal between the two eyes.

C. tissue spikes that are equally tall and sharp.

The forehead and cheek rests on the phoropter are cleaned A. after each patient with water. B. periodically with a 1:10 dilution of liquid bleach. C. with soap and water, soaked in alcohol or boiled In water. D. after each patient by a sterilization process only.

C. with soap and water, soaked in alcohol or boiled In water. The semi-permanent face shields furnished with the phoropter are made of white nylon. This material can be washed with soap and water, soaked In alcohol or boiled in water.

What is the size of the visual field tested by an Amsler Grid held at 28cm to 30cm? A. 5 degrees B. 10 degrees C. 15 degrees D. 20 degrees

D. 20 degrees The Amsler grid is used to test the central 20 degrees of the visual field. The Amsler grid was devised to detect abnormalities in the central 20 degrees in the field of vision.

Which of these exophthalmometry protrusion measurements Is most abnormal. in terms of proptosis? A. 22 B. 24 C. 26 D. 28

D. 28 Minimum of 22mm to a more marked 28mm

What is the preferred diagnostic procedure to test for keratoconus? A. Visual acuity B. Biomicroscopy C. Slit lamp exam D. Corneal topography

D. Corneal topography Corneal topography is the gold standard for the diagnosis of an forms of keratoconus.

Only visual field defects that arise from disturbances in what area of the retina, such as those caused by a vitreous or macular hemorrhage, result In awareness of something black before a patients eyes? A. Right side B. Left side C. Back D. Front

D. Front Only field defects that arise from disturbances in the front of the area of the retina, such as those caused by a vitreous or macular hemorrhage, results in awareness of something black before a patient's eyes.

What is the proper name for an astigmatic eye with the anterior focal line In front of the retina and the posterior focal line behind the retina? A. Compound hyperopic astigmatism B. Compound myopic astigmatism C. irregular astigmatism D. Mixed astigmatism

D. Mixed astigmatism In mixed astigmatism one focal point lies behind the retina, whereas the other focal point lies In front of it.

In the case of a one.year old child with an infantile left eactropla and deep left amblyopia, which notation would denote the visual acuity? A. CSM B. CSUM C. CLEM D. UCSUM

D. UCSUM

When evaluating a patient for cataract surgery, which of the following systemic illnesses is LEAST important? A. Cardiac problems B. Diabetes C. Hypertension D. Urinary incontinence

D. Urinary incontinence.

The DK value of contact lens material is the A. measurement of the light transmittance of the material. B. measurement of the refractive Index of the material. C. oxygen transmissibility of the material. D. diffusion, solubility, and movement of oxygen In the lens material.

D. diffusion, solubility, and movement of oxygen In the lens material. The permeability of the plastic, the ease with which oxygen passes through it, is called the DK level of the material. The oxygen transmission through a given material is a laboratory measurement, where D is the diffusion coefficient for oxygen movement In lens material and K is the solubility coefficient of oxygen In the material.

A retrobulbar injection places medication into the A. bulbar conjunctiva. B. conjunctiva. C. eyeball. D. muscle cone.

D. muscle cone. Retrobulbar injection of anesthetic agents into the muscle cone is used for intraocular surgery.

Involuntary, rhythmic to-and-fro oscillations of one or both eyes Is referred to as A. ptosis B. proptosts. C. emmetropla. D. nystagmus.

D. nystagmus.

Streak retinoscopy is a (n) A. retinal exam for diabetic retinopathy. B. subjective method for measuring refractive error. C. test performed by laser. D. objective method for measuring refractive error.

D. objective method for measuring refractive error. A streak retinoscope allows technical personnel to measure objectively the optical power of the eye.

The presence of an afferent pupitiary defect may be caused by A. damage to the iris sphincter muscle. B. symmetric damage to the afferent visual system. C. asymmetric cataracts. D. optic nerve disease.

D. optic nerve disease. Relative Afferent Pupillary Defect (RAPD) Is generally a sign of optic nerve disease. Optic nerve disease produces a significant RAPD.

A patient who hes a total deficiency of the red visual pigment Is classified as A. deuteranomalla. B. deuteranopia. C. protanomalia. D. protanopia

D. protanopia A deficiency of red-sensitive cones (protanomaly) results In poor red-green discrimination and so the red end of the spectrum appears dimmer than normal.

Proliferative diabetic retinopathy resulting in neovascularization can contract to form a fibrovascular mass that can pull on the retina and lead to A. conjunctivitis. B. keratoconus. C. retinoschisis. D. retinal detachment.

D. retinal detachment. Neovascularlization is the major sign of proliferative diabetic retinopathy. Proliferative diabetic retinopathy can lead to either progressive traction retinal detachment or, if a retinal tear is produced, rhegmatogenous retinal detachment. Neovascularizalion can contract to form a fibrovascular mass that can pull on tee retina and lead to retinal detachment.

A laser is composed of alt of the following except: a) An ophthalmoscope b) A chemical substance (such as gas or crystal) c) A power source d) An amplifying mirror system

a) An ophthalmoscope. A laser requires a chemical substance to supply electrons, a power source to excite the electrons (which then produce photons), and amplifying mirrors to intensify the reflected photons An ophthalmoscope is not required.

A comparison of the speed of light in air to the speed of light through a substance is: a) IR (Snell's Law) b) Angle of refraction c) Internal reflection d) Optical interference

a) IR (Snell's Law) The IR of a substance is found by dividing the speed of light in air by the speed of light through the substance. This is known as Snell's Law.

The ray of light that enters a transparent medium is termed: a) Incident ray b) Divergent ray c) Emergent ray d) Parallel ray

a) Incident ray The incident ray is the ray that first strikes and enters a medium. A divergent ray has been refracted outward. The emergent ray is the ray as it exits the medium. A parallel ray is straight.

All of the following regarding the optical center of a lens is true except: a) It always coincides with the geometric center of the lens b) Light rays passing through it are not refracted c) It also is known as the nodal point d) It should be centered in line with the patient's visual axis

a) It always coincides with the geometric center of the lens. The optical center does not always coincide with the geometrical center of a lens. The key word here being always.

The focal length of a lens: a) Is the distance between the lens and the focal point b) is the dioptric power of the lens c) Is the point where light is focused d) is related to the axis of the cylinder

a) Measure the distance between the lens and the focal point, and you will have measured the focal length. It is related to the dioptric power of the lens in that the stronger the lens, the shorter the focal length.

Which color has the longest wavelength: a) Red b) Yellow c) Green d) Blue

a) Red. Red has the longest was wavelength: 650 nanometers.

A 2.00 diopter prism displaces an object 1 cm at a distance of: a)0.2 m b)0.5 m c) 1.5 in d)5.0 cm

b) 0.5m The formula for figuring prism displacempelanct is P+C/D, where P is the prism power, C is the displacement of the object in cm, and D is the distance from the prism in meters. To plug in this problem: 2=1/D. Do algebra and multiply both sides by D/1, yielding 2D=1. Now divide both sides by 2; D=1/2. 1/2 = 0.5m.

A 1.00 diopter spherical lens focuses light at: a) 1/2m b) 1 m c) I cm d) I yard (yd)

b) 1 m A 1.00 diaopter lens focuses light at 1 m. Technically, the light entering the lens must be parallel for this to hold true.

The range of was lengths in the visible spectrum is: a) 100 to 400 nanometers b)400 to 800 nanometers c) 450 to 650 nanometers d )400 to 800 meters (m) immediately on either side of the visible spectrum are the invisible flight segments of: ...ginfrared and ultraviolet b) X-rays and radio waves

b) 400 to 800 nanometers Depending on which reference is consulted, visible light is in the range of 400 to 800 nanometers. (Be sure to watch the units of measurement gis en in an answer. "Meters" in answer d should have indicated that it was incorrect.)

Light traveling through a prism will be bent toward the prism's: a) Apex b) Base c) Center d) Smallest angle

b) Base. Light traveling through a prism is bent toward the prism's base.

If light passes through a lens and the rays are bent toward each other after exiting, this is known as: a) IR b) Convergence c) Zero vergence d) Divergence

b) Convergence occurs when light rays are brought together (bent inward) by the lens.

The phenomenon of fluorescence is used: a) During radial keratotomy b) During angiography c) During slit lamp photography d) During fundus photography

b) During angiography. Fluorescence is used in fluorescein angiography. The blue filters excite the dye, causing it to fluoresce.

The acronym "laser" stands for. a) Light assisted surgery by elimination of radiation b) Light amplification by stimulated emission of radiation c) Light amplification of super electron reduction

b) Laser stands for light amplification by stimulated emission of radiation.

When light passes through a transparent medium, it may travel straight through (transmission) or its path may be altered. This altering or bending property of a medium is known as: a) Reflection b) Refraction c) Absorption d) Tropism

b) Refraction The quality of a medium to bend light is called refraction. In deflection, the rays are bounced off of the surface. Absorbed light does not pass through a medium. Tropism actually refers to the phenomenon of plants bending toward a light source.

The denser the substance, the more slowly light passes through it, and: a) The lower the IR b) The higher the IR c) The more transparent it is d) The more suitable it is for use as an ophthalmic lens

b) The higher the IR. A substance with a high IR is more dense, and slows down the light passing through it

At a distance of 2 m, a 12 diopter prism would displace an object: a) 6 cm b) 2.4 m c) 24 cm d) 6 m

c) 24cm Plug in to get:12 = C/2. Multiply each side by 2/1, and 24=C. The answer is 24cm. Be sure to pay attention to units of measurement! Another correct answer would have been 0.24m.

A 1.00 diopter prism bends light: a) I centimeter (cm) at a distance of I cm from the prism b) I mat a distance of I cm from the prism c) 1 cm at a distance of I m from the prism d) 1 m at a distance of I m from the prism

c) A 1.00 diopter prism bends light at I cm at a distance of 1 m from the prism.

A spherical lens refracts light: a) Not at all b) In one direction only c) Equally in every direction d) At 90 degrees from its axis

c) Equally in every direction. A spherical lens refracts light equally in every direction. This is evidenced by the fact that you can shine a light through a plus lens and focus it to a point.

The particle theory of light postulates that light is made up of particles called: a) Protons b) Neutrons c) Photons d) Electrons

c) Photons. Photons are the particles of light put forth by the particle theory. Protons, neutrons, and electrons are all parts of an atom.

Polarization uses filters to cut out all light rays except: a) Those of the same wavelength b) Wavelengths traveling in the same direction c) Wavelengths vibrating in the same direction d) Ultraviolet and infrared

c) Polarization filters out all light rays except those that are vibrating in the same direction.

The IR of crown glass is: a) 0 b) 1.00 c) 1.33 d) 1.50

d) 1.50. Depending on which reference is consulted, the IR of crown glass is 1.50. Light traveling through a vacuum is zero, through air is 1.0, and through water is 1.33.

If light passes through a lens and the rays are spread apart after exiting, this is known as: a) index of refraction (LR) b) Convergence c) Zero vergence d) Divergence

d) Divergence. If the light is spread apart by the lens, the rays are said to be divergent.

The point at which a lens forms an image (whether real or virtual) is the: a) Nodal point b) Conoid of Sturm c) Focal length d) Focal point

d) Focal point The focal point is the place where the lens focusses incoming light. The focal point may be real (projected on a screen) or virtual (exists in theory but cannot be projected).

The image of an object viewed through a prism: a) is real and shifted toward the base b) is virtual and shifted toward the base c) is real and shifted toward the apex d) is virtual and shifted toward the apex

d) Is virtual and shifted toward the apex. Because light is bent toward the base, the image appears to be shifted toward the apex. A real image can be projected on a screen, while a virtual image cannot.

Ophthalmic lasers perform their work by: a) Photogenicity b) Energizing protons in the tissue c) Fluorescence and polarization d)Photocoagulation and photodisruption

d) Photocoagulation and photodisruption Lasers accomplish their work by photocoagulation (welding) and photodisruption (vaporizing).

The displacement of an object 5 cm at a distance of 1 m would require: a) 0.5 diopters b) 1.0 diopters c) 2.0 diopters d)5.0 diopters

d) Plug in again: P .= 5/1. Thus P a 5.0 diopters.

In basic ocular testing, polarized glasses are used: a) To test color vision b) To simulate vision with cataracts c) In the Worth 4 dot test d) To test stereo vision

d) To test stereo vision. Polarized glasses are used in stereo vision testing because the filters (lenses) can be positioned so that one eye sees one part of an image and the other eye sees another part.

The electromagnetic theory of how light travels states that light radiates in the form of: a) Spectrums b) Lines c) Circles d) Waves

d) Waves. The electromagnetic theory postulates that light travels in waves.