Chapter 31; Opthalmology and Otolaryngology

Retinal Layer

Light receptor that transforms optic signals into nerve impulses.

Cornea

Light refraction

Lens

Light refraction

Eyelid

Protects eye

Dynamic Equilibrium

Relating to balance when moving at an angle or rotating.

Static Equilibrium

Relating to balance when moving in a straight line.

Ciliary body

Secretion of vitreous fluid; changes the shape of the lens.

Corneal Abrasions

Symptoms of corneal abrasion include pain, inflammation, tearing, and photophobia. The abrasion usually is caused by a foreign body in the eye or by direct trauma (Possibly by a contact). Diagnosis: includes installation of fluorescein stain which can be used with a cobalt blue filtered light to visualize the abrasions, which will appear green. Treatment: Can be treated with antibiotic opthalmic ointment to prevent infection, studies now show that patching does not reduce the patients pain and may actually prolong healing time. Healing: They usually heal in 24 to 72 hours.

Eye Irrigation

The ey is irrigated to relieve inflammation, remove drainage, dilute chemicals, or wash away foreign bodies. Sterile technique and equipment must be used to prevent contamination.

Blinking

The eye blinks about every 2 to 3 seconds. Blinking causes the lacrimal gland located in the superior outer portion of the upper eyelid to secrete tears. (After the lacrimal gland ssecrete tears they drain into the nasal cavity through the nasolacrimal duct. )

Anatomy of the eye

The eye canbe divided into the ocular adnexia, the structures that surround and support the function of the eyeball, and the structures of the eye itself.

Eyeball

The eyeball consists of 3 layers: 1.) The outermost layer is made up of the white, opaque sclera and the transparrent cornea. (Also known as the white of th eye). 2.) The middle layer is made up of the choroid, the iris, and the ciliary body. The iris is the colored portion of the eye. The iris contains muscles that regulate the size of the pupil depending on The intensity of light. (Becomes smaller in bright light and opens wider in dim light. ) 3.) The inner lyer of the ee includes the retina posterior portion and the len in the anterior portion. The delicate tisue of the retina is composed of light sensitive neurons called rods and cones.

Biconvex

Having two outward curving surfaces, on a lens.

Iris

Light absorption and regulation of pupil width.

Lacrimal glands

Produce tears

Risk factors for Otitis Media

-Sex (Male) - Age (INfants and younger children; 6 to 18 months) -Premature birth - Family history -siblings with infection -Seasonal factors ( most common during clod and flu season) -Underlying disease (Lceft palate, down syndrome, asthma, allergies) - Ethnicity ( native ameican and alaskan inuit) -Cochlear implants

Cataract

A cataract is a cloudy or opeque area in the normally clear lens of the eye that blocks the passage of light into the retina, causing impaired vision. This condition may result from injury to the eye, exposure to extreme heat or radiation, or inherited factors. Typically occur after age 60. With advanced cataracts the pupil of the eye appears white or gray.

Ototoxic

A medicine or substance capable of damaging cranial nerve VIII or the organs of hearing and balance.

Tinnitus

A noise sensation of ringing heard in one or both ears.

Chalazion

A small cyst that results from blockage of a meibomian gland (sebaeous gland) and lubricates the posterior margin of each eyelid. May diappear randomly or may need to be surgically removed.

Equilibrium

A state of rest or balance due to the equal action of opposing forces.

Serous

A thin, watery serum-like drainage.

Psoriasis

A usually chronic, recurrent skin disease marked by bright red patches covered with silvery scales.

Accommodation

Adjustment of the eye that allows a person to see various sizes of objects at different distances.

Adiologist

Allied healthcare professional who specializes in the evaluation of hearing function , detection of hearing impairment, and determination of the anatomic site of impairment.

Seborrhea

An excessive discharge or sebum from the sebaceous glands, forming greasy scales or crusty areas on the body.

Tonometer

An instrument used to measure intraocular pressure.

Optometrist

An optometrist is not a medical doctor, but he or she is licensed and has earned a degree as a doctor of optometry (OD).

Miotic

Any substances or medication that causes constriction of the pupil.

Rods

Are highly sensitive to light and can function in dim light. (Rods and cones convert light into nerve impulses.)

Opticians

Are trained to fill prescriptions written by opthalmologists and optetrists for corrective lenses by grinding the lenses and dispending eyewear.

Central fovea

Area of sharpest vision

Presbyopia

As people age, the lens of the eye becomes less flexible and the ciliary muscles weaken; chnaging the point of focus from the distance to near becomes difficult. Resulting in difficulty seeing at reading level. -This actually starts at age 10, but most casespeople do not report an alteration invision until their early 40s.

Audiometric Testing

Audiometr measures the lowest intensity of sound an individual can hear. The patient, frequently a child, is assisted in placing the headphones over the ears. The patient is asked to sognal when he hears the sound.

Choroid

Blood supply

Audible

Capable of being heard.

Macula Lutea

Center of the retina; contains the fovea centralis, the area of most highly acute vision.

Impacted Cerumen

Cerumen is normally a soft, yellowish, waxy substance that ubricates the external auditory canal. -Impacted cerumen that has been pushed against the eardrum is a common casue of conductive hearing loss because sound vibrations cannot pass through the cerumen to initiate movement of the tympanic membrane. -Excessive secretion of cerumen can gradually cause hearing loss, tinnitus, a feeling of fullness, and otalgia (ear pain). * Cerumen can be removed by softening the wax with oily drops and then irrigating the ear with warm water until the plug is removed.

Suppurative

Characterized by the formation of discharge of pus.

Cones

Color vision

Cornea

Covers the center of the eye.

Glaucoma

Glaucoma is characterized by increased intraocular pressure (IOP). It rarely occurs in people under 40, but is ussually seen in people over 60. The cause is unknown, but a hereditary tendency toward development of the most common forms has been noted. Glaucoma is responsible for 12% of all cases of blindness.

Vascular

Having (Blood) vessels that conduct or circulate liquids (Blood).

Ishihara Color vision test

Defects in color vision are classified as congenital or acquired. Congenital defects are caused by an inherited color vision defect and are found most often in males. Acquired defects are caused by eye injury or disease. -The test assesses the perception of primary colors and shades of colors. * The test uses 14 color plates. The basic test consists of plates 1 through 11. PLates 12 through 14 are used if the patent appears to be having difficulty with red-green differentiations. If the score is 10 or higher the patient is within the average range. If the score is 7 or lower, the patient issuspected of having color deficiency.

Distance Visual Acuity

Determining distance visual acuity frequently is part of a complete physical examination. The chart most commonly used is the snellen alphabetical chart. This chart displays various letters of the alphabetical, which the patient must identify in even smaller font sizes. The patient must not be alloweded to study the chart before taking the test. -The chart should be hung at the patients eye level and illuminated with maximum light, without glare on the chart. * record the results of each eye seperately and as fractions. The numerator (top number) is the distance of the patient from the chart (always 20 feet), and the denominator (bottom number) is the lowest line read satisfactory by the patient.

Rods

Distinguish light from dark and perceive shape and movement

Vertigo

Dizziness ; abnormal sensations of movement when there is none.

Diplopia

Double vision

Amblyopia

Dull or dim vision, with no apparent organic defect.

Ocular Adnexa

Each of our paired eyes is encased in a protective, bony socket called the orbit. Only 1/6 of the eyeball lies outside the orbit. The eyelid helps protect the orbit from trauma. The eyebrows help keep irritants out of the eye and the eyelid helps protect and trap foreign particles by lining the margins of the eyelids.

Sclera

External protection

Photophobia

Extreme sensitivity to light.

Signs and symptoms of refractive errors

Eyeglasse and contact lenses ae the traditional treatments for visual acuity problems caused by refractive errors. But the problem can be corrected surgically.

Disorders of the eye: Refractive errors

Four major types of refractive errors result when the eye is unable to focus light effectively on the retina.

Cones

Function in bright light and detect color. (Rods and cones convert light into nerve impulses.)

Infections of the eye

Hordeolum (sty): A localized infection of sebaceous gland of the eyelid. The area is inflammed, swollen, and painful. It is treated with warm compressions and topical or systemic antibiotics.

Conjunctivitis

Inflammation of the conjuctiva caused by irritation, allergy, or bacterial infection. Bacterial conjunctivitis (pinkeye) is highly contagious and produces a purulent discharge. Symptoms include inflammation, swelling, and itching of the sclera, photo-phobia, and tearing.

Keratitis

Inflammation of the cornea that results in superficial ulcerations. It can be caused by the herpes simplex virus, bacteria, or fungi, or it may develop as a result of corneal trauma. Symptoms include inflammation, tearing, pain, and photophobia. The condition is treated with opthalmic ointments, eyedrops, and use of an eye patch.

Blepharitis

Inflammation of the glands and lash follicles along the margins of the eyelids that may be caused by staphylococcal infection, allergies, or irritation. Syptoms include itching and inflammation along the eyelash margins; the condition is treated with antibiotic opthalmic ointment.

Sensorineural

Involving the sensory nerves, especially as they affect hearing.

Binocular

Involving, relating, or seeing with both eyes.

Ear Irrigation

Irrigation of the ear is done to remove excessive or impacted cerumen, to remove a foreign object, or to treat the inflamed ear with an antiseptic solution. -Some discomforts the patient may experience during ear irrigation include vertigo, coughing, or a tickle in the back of the throat.

Strabismus

Is a failure of the eyes to track together, which means that both eyes do not look in the same direction at the same time. Caused by- Adults- diabetes, muscular dystrophy, or hypertension or head injury. Children- Causd by weakness in the muscles that control eye movement.

Conjunctiva

Is a thin mucous membrane that lines the eyelid.

Rinne test

Is designed to compare air conduction sound with bone conduction sound. In this test the stem of the vibrating fork is placed on the patients mastoid process and the patient is insructed to raise a hand when the sound disappears.

Refraction

Is the ability of the lens of the eye to bend parallel light rays coming into the eye so that the rays are focused simutaneously on the retina.

Otorhinolaryngology

Is the medical speciality that delas witht the ear, nose, and throat. It is frequently reffered to as otolaryngology or even as a single specialty of otology or larynology usually reffered to as ear, nose, and throat (ENT).

Opthalamology

Is the science of the eye and its disorders and diseases. A physician who specializes in the diagnosis and treatment of disorders of the eye is an ohthalmologist.

Menieres disease

It is a disorder of the inner ear. I tis charaterized by vertigo, tinnitus, progressive hearing loss, and sometimes a feeling of pressure or fullness in th ear. Ussually only affects one ear.

Tympanogram

May be done to determine the air pressure of the middle ear and the mobility of the tympanic membrane.

An error of refraction

Means that the light rays are not refracted or bent properly and consequently do not focus correctly on the retina.

Instillation of Eye Medication

Medication may be instilled into the eye to treat an infection, soothe an eye irritation, anesthetize the eye, or dilate the pupils before examination or treatment.

Instilling Otic Medications

Medication ordered for ear instillation is given to soften impacted cerumen, to relieve pain, or as an antibiotic drop for an infectious pathogen.

External ocular muscles

Move the eyelid

Myopia (Nearsightedness)

Myopia occurs when light rays entering the eye focus in front of the retina, causing objects at a distance to appear blurry and dull.

Near Visual Acuity

Near visual acuity can be tested with the near vision acuity chart. This test is given to screen for presbyopia or hyperopia. If th patient wears corrective lenses, they should be worn during the test. Should be given in a well lit room with the card 14 to 26 inches away.

Astigmatism

Occurs hen light rays entering the eye are focused irregulary. Opthalmologists describe the lens as being shaped like a football rather than a sphere, such as a basketball. -this causes light rays to be unevely or diffusely focused on the retina, Resulting in blurred vision. It is like attempting to focus on objects seen through a wavy piece of window glass.

Inner Ear

Once sound is conducted to the oval window, it is transmitted to a structure called the labrynth, or the inner ear. The inner ear is divided into the cochlea and the semicircular canals. which are joined by the vestibule. The semicircular canals and vestibule function to maintain equilibrium.

Optic nerve

One of a pair of nerves that transmit visual stimuli to (cranial nerve 2) the brain.

Earwax

Or cerumen, is secreted by modified sweat glands within the external auditory canal. Both the hair and the waxy cerumen help prevent foreign objects from reaching the eardrum. The canal has a slightly curved shape and is approximately 1 inch long.

Assisting with Opthalmology Treatments

Patients with ophthalmology conditions are prescribed a variety of meds. The following are the most common- Topical antibiotic ointment- Used to treat bacterial infections. Antinflammatory Agents- Used to reduce inflammation. Antiinfectives- Used to treat viral infections.

Assisting with opthalmology examination

The eyelids are examined for edema, which may be the result of nephrosis, heart failure, allergy,, or thyroid deficiency. Blepharoptosis also called ptosis, is drooping of the upper eyelid that can be caused by a disorder of the third cranial nerve, muscular weakness as seen in muscular dystrophy, or myasthenia gravis.

Presbycusis

The hearing loss that affects older adults, is caused by a reduction in the number of receptor cells in th organ Corti and also is classified as sensorineural loss.

Medulla Oblongata

The lowest part of the brain, continuous with the top of the spinal cord.

Macular Degeneration

The macula Lutea, the part of the retina near the optic nerve, defines the center of the field of vision. Macular degeneration is progressive deterioration of the macula lutea which causes loss of centrall vision; making the patient only see the edges of the visual field. -Leading cause of blindness in poeple older than 50. 2 kinds occur- dry or wet macular degenration.

Middle Ear

The middle ear is an air filled caivty that contains three tiny bones called the ossicles: Malleus, incus, and stapes. Tiny ligament slink the bones to form a bridge from the tympanic membrane to the inner ear.

Thalamus

The middle part of the brain through which sensory impulses pass to reach the cerebral cortex.

Otosclerosis

The ossicles of the middle ear (Malleolus, incus, and stapes.) become fused and act as a single unit instead of individual bones.

Outer (external) Ear

The outer ear consists of the auricle, or pinna. This is the fleshy part of the ear that can be seen on the side of the head. The next structure is the external auditory canal, the tube that extends from the auricle into the typanic membrane (eardrum).

Auditory cortex

The region of the cerebral that receives auditory data.

Motion sensitivity or motion sickness

The semicircula canals detect dynamic equilibrium. Within the vestibule, two saclike structures function to establish the bodys static equilibrium. With repetitive or excessive stimulation to the equilibrium receptors, some people become nauseated and may vomit. This is called motion sickness.

Hertz

The unit of measurement used in hearing examinations; a wave frequency equal to one cycle per second.

Anatomy of the ear

The visible portion of the ear is only a small part of the actual organ of hearing. Most of the sensory structure lies hidden in the temporal bone of the skull. The ear is divided into the outer, middle, and inner ear.

Evert

To turn the eyelid inside out; the provider typically does this to inspect the area for foreign bodies.

Tuning fork Test

Tuning fork tests measure hearing by air conduction and bone conduction. Remember that in bone conduction, the sound vibrates throughthe cranial bones to the inner ear. -To activate the fork the prvider holds it by the stem and strikes the tines softly on the palm of the hand. The two tests used to evaluate hearing are the weber and rinne test.

Otitis

Two common types: Otitis externa (swimmers ear): May be cuased by dermatologic conditions such as seborrhea or psoriasis, trama to the canal, or continuous use of earplugs or earphones. Swimmers frequently have otitis externa becuse water collects in the ears and mixes with cerumen to form an ideal culture medium for bacteria and fungus. Causes- inflammation and swelling, severe pain, hearing loss, and possible purulent drainage. Otitis Media: is an inflammation of the normally air-filled middle ear that results in a collection of fluid bhind the tympanic membrane. It can be serous or suppurative. (children are more likely to suffer from these because thier eustachian tube is shorter, narrower, and more horizontal.)

Disorders of the ear: Hearing loss

Two problems result in hearing loss: a conduction problem and a sensorineural impairmnet. Conductive hearing loss: Is caused by a problem originating in the external or middle ear that prevents sound vibrations from passing through the external auditory canal. Sensorineural impairment: results form the abnormality of the organ of corti or of the auditory nerve. Viral infections can result in hearing loss, as can head trauma or certain ototoxic medications.

Weber test

Used if the patient reports that hearing is better in one ear than in the other. Th evibrting fork is placed in the center of th top of the head, and the patient is asked in which ear the tone is louder, or if the tone is the sam ein both ears.

Gonioscopy

Used to diagnose glaucoma and to inspect ocular movement.

Hyperopia (Farsightedness)

When light enters the eye and focuses behind the retina, a person has hyperopia. This disorder occurs when the eyeball is too short from the anterior to the posterior wall. -An individual with hyperopia has difficulty seeing objects that are close/

Nystagmus

a constant, involuntary movement of one or both eyes is called nystagmus. They eye can move in any direction and the movement is accompanied by blurrd vision.