L8 - Visual & Auditory Disorders

What are refractive errors?

Most common vision problem: light doesn't focus on the retina -> blurred vision; corrected with glasses, contacts, laser surgery or lens implant

What is myopia?

Nearsighted: light focuses in front of the retina, distance is blurry; most common (about 30% of Americans)

What is hyperopia?

Farsighted: light focuses behind the retina, near is blurry

What is presbyopia?

Age-related loss of accommodation starting in the 40s as the lens stiffens; hard to focus up close

What is astigmatism?

Uneven corneal curvature distorts vision

What is aphakia?

Absence of the lens

What is strabismus?

Eyes can't focus together

What is legal blindness?

Best-corrected vision in the better eye of 20/200 or less, or a visual field of 20 degrees or less

What are the main causes of US blindness?

Cataracts, glaucoma, AMD, diabetic retinopathy

How do you communicate with a pt who is blind?

Normal tone, introduce yourself on approach, make eye contact, say goodbye when leaving, use sighted-guide technique

What sleep problem can lack of light cause?

Circadian sleep disorder (treat with melatonin)

What are concerns for older adults with vision loss?

Fall risk, independence, dexterity for eye drops

What is the first action for a chemical splash to the eye?

Immediate continuous irrigation (e.g. Morgan lens)

Which chemical burn of the eye is worst and why?

Alkaline (pH above 7) bc it penetrates the eye; acids damage the cornea but don't penetrate

What is a sty (hordeolum)?

Usually Staph aureus eyelid infection; treat with warm compresses

What is a chalazion?

Eyelid granuloma

What is blepharitis?

Bilateral eyelid inflammation; treat with antibiotic ointment

What is conjunctivitis and its types?

Infection or inflammation of the conjunctiva: bacterial, viral, chlamydial or allergic; itching is the defining symptom

What is bacterial conjunctivitis?

Pink eye, usually Staph aureus; spreads to the other eye; self-limiting, antibiotic drops may shorten it

What is viral conjunctivitis?

Tearing, foreign body feeling, redness, mild photophobia; adenovirus spreads by direct contact and contaminated pools

What is the care for epidemic keratoconjunctivitis?

Most serious adenoviral form: ice packs, artificial tears, dark glasses

How do you prevent the spread of conjunctivitis?

Hand washing and individual or disposable towels

What is trachoma?

Chlamydial infection; leading cause of blindness worldwide

What is the most common cause of corneal blindness in developed countries?

HSV keratitis

What causes Acanthamoeba keratitis?

Contaminated contact lens solution

What are manifestations and care of a corneal ulcer?

Pain and foreign body sensation; eye drops every hour for 24 hrs; untreated can perforate and need a transplant

What is dry eye?

"Sand in the eye" that worsens through the day; artificial tears, cyclosporine

What is a cataract?

Opacity of the lens; removal is the most common surgery in the US

What are risk factors for cataracts?

Aging, trauma, smoking, alcohol, radiation, UV light, steroids; people with diabetes get them younger

What are manifestations of cataracts?

Gradual decrease in vision, abnormal color perception, glare worse at night when the pupil dilates

What can pts do before surgery?

New glasses, magnifiers, brighter light, avoid night driving

What is the only cure for cataracts?

Surgery; most common is phacoemulsification with an intraocular lens implant

What are mydriatic and cycloplegic eye drops?

Mydriatic: dilates the pupil; cycloplegic: paralyzes accommodation; wear dark glasses for photophobia; watch for tachycardia and CNS effects

What is the teaching after cataract surgery?

Antibiotic and steroid drops; no bending, stooping, coughing, straining or lifting; nighttime eye shield; report pain, drainage, redness, vision loss

What is the most important teaching before eye drops or patch changes (her question)?

Wash hands

Why check acuity in the unoperated eye?

The pt relies on that eye after surgery

What safety risk does an eye patch cause?

No depth perception, so prevent falls

Why avoid bending and the Valsalva maneuver after eye surgery?

They raise intraocular pressure

What is retinopathy?

Microvascular damage to the retina, most often from diabetes or hypertension

What is nonproliferative diabetic retinopathy?

Most common form: microaneurysms, swelling, hard exudates

What is proliferative diabetic retinopathy?

Advanced: fragile new vessels leak and bleed -> severe vision loss; treat with laser photocoagulation

What is hypertensive retinopathy?

Hemorrhages and cotton-wool spots; severe HTN can cause papilledema and sudden vision loss; treat the BP

What is retinal detachment?

Sensory retina separates from the pigment layer, usually from a tear; an emergency

What are manifestations of retinal detachment?

Flashes of light, floaters, a ring in the visual field, then painless vision loss "like a curtain"

What is the first diagnostic step for retinal detachment?

Measure visual acuity

What are treatments for retinal detachment?

Laser photocoagulation or cryopexy for tears; scleral buckling or other surgery; special head positioning after to keep the gas bubble in place

What is AMD?

Age-related macular degeneration: leading cause of irreversible central vision loss

Compare dry vs wet AMD

Dry (about 90%): drusen, slow painless loss; Wet (about 10%): abnormal leaky vessels, rapid loss

What are risk factors for AMD?

Age, smoking (biggest modifiable), family history, obesity, HTN, being White, female

What are manifestations of AMD?

Blurred or dark central vision, scotomas (blind spots), metamorphopsia (straight lines look wavy)

What tool tracks AMD?

Amsler grid

What are treatments for AMD?

Wet: anti-VEGF injections into the eye every 4-6 weeks, photodynamic therapy; vitamins C and E, beta-carotene, zinc, lutein; stop smoking

What is the teaching after photodynamic therapy?

Avoid sunlight and bright light for 5 days

What is glaucoma?

Increased IOP from imbalanced aqueous inflow and outflow damages the optic nerve; second leading cause of permanent blindness in the US

What is normal IOP?

10-21 mm Hg

Who is at higher risk for glaucoma?

Black people and older adults; many are unaware

What is primary open-angle glaucoma (POAG)?

Most common: drainage through the trabecular meshwork slows; no pain; gradual peripheral loss -> tunnel vision; optic disc cupping

What is acute angle-closure glaucoma (AACG)?

Ocular emergency: sudden severe eye pain, N/V, colored halos, blurred vision, red eye; IOP can exceed 50

What triggers AACG?

Pupil dilation: mydriatic drugs, darkness, emotional excitement

What is the treatment for AACG?

Drugs (carbonic anhydrase inhibitors, hyperosmotic agent) and laser or surgical iridotomy

(T/F) Vision lost to glaucoma can be restored

False; it is preventable but not reversible; drugs control but don't cure

What is the first-line drug class for POAG and how does it work?

Prostaglandin agonists (latanoprost): increase aqueous outflow

How do beta-blocker eye drops (timolol) work and when are they avoided?

Decrease aqueous production; avoid with bradycardia, heart block, HF; nonselective ones with asthma or COPD

How do miotics (pilocarpine) work?

Constrict the pupil and open the trabecular meshwork to increase outflow; reduce vision in dim light

How do carbonic anhydrase inhibitors work in glaucoma?

Decrease aqueous production; allergic reactions can occur with sulfa allergy

How often are eye exams recommended?

Age 40-54: every 2-4 years; 55-64: every 1-3 years; 65+: every 1-2 years; more often if high risk

What are causes of external otitis?

Usually Staph aureus or fungi (Candida, Aspergillus); from swimming, trauma, piercing, infection

What is malignant external otitis?

Pseudomonas infection in older adults with diabetes

What are manifestations of external otitis?

Otalgia (ear pain), swollen canal with muffled hearing, serosanguineous or purulent drainage, fever

What is the treatment for external otitis?

7-14 days of moist heat, mild analgesia and otic drops

How is impacted cerumen removed?

Irrigate with body-temperature solution

Who removes a foreign body from the ear?

Only a provider, so it isn't pushed farther in

How should pts clean their ears?

Washcloth and finger, never cotton-tipped applicators

Why are children more prone to otitis media?

Auditory tube is shorter, narrower and flatter

What are manifestations of acute otitis media?

Red, bulging TM with no landmarks, fever, malaise, drainage, reduced hearing

What is the treatment for acute otitis media?

Oral antibiotics and drops; antihistamines and nasal steroids if allergic; myringotomy with tube for recurrence

What is a myringotomy?

Incision in the TM to release pressure and fluid; a tympanostomy tube ventilates the ear

What is otitis media with effusion?

Fluid without acute infection: fullness, plugged or popping ears, muffled hearing; usually resolves on its own, no antibiotics needed

What are chronic otitis media and mastoiditis?

Purulent exudate, may be painless, hearing loss, nausea, dizziness, cholesteatoma; goals: clear infection, repair perforation, preserve hearing

What is the teaching after ear surgery?

Back with head raised; no bending, straining or flying; no nose blowing for 6 weeks; cough or sneeze with mouth open; keep ear dry; report drainage or severe dizziness

What does a vestibular labyrinth problem cause vs an auditory labyrinth problem?

Vestibular: vertigo; Auditory: tinnitus and sensorineural hearing loss

What is Ménière disease?

Too much endolymph, usually in one ear, ages 40-60; no cure

What are manifestations of Ménière disease?

Sudden attacks of vertigo, N/V, nystagmus lasting minutes to hours, after ear fullness, tinnitus and muffled hearing; can have drop attacks

What is the care during a Ménière attack?

Quiet dark room, avoid sudden head movements, close eyes until vertigo stops, no TV or flickering lights, fall precautions, IV fluids if vomiting

Which drugs are used in Ménière attacks?

Antihistamines (meclizine), anticholinergics, benzodiazepines, antiemetics

What is the long-term care for Ménière disease?

Low-salt diet, limit caffeine and alcohol, stop smoking, manage stress, diuretics; gentamicin injections to cut endolymph production

What is the safety teaching for Ménière disease?

Lie or sit when dizzy, no underwater swimming, avoid high places

What is BPPV?

Loose calcium crystals in the semicircular canals: brief spinning with head movement, nystagmus, nausea

What is the key difference between Ménière disease and BPPV?

Ménière has hearing loss; BPPV is vertigo only

What treats BPPV?

Epley maneuver (moves the crystals; can be taught to pt)

What is an acoustic neuroma?

Benign tumor where CN VIII enters the internal auditory canal; onset 40-60 (her slides)

What are manifestations of acoustic neuroma?

One-sided progressive sensorineural hearing loss, one-sided tinnitus, mild vertigo, reduced touch sensation in the posterior ear canal

What is the key test for acoustic neuroma?

MRI

What is the treatment for acoustic neuroma?

Radiation for small tumors; surgery for any size

What should be reported after acoustic neuroma surgery?

Clear, colorless nasal drainage: possible CSF leak

What is tinnitus?

Sound with no external noise (ringing, buzzing); can be the first sign of hearing loss; often from noise exposure or drugs

What is the strongest predictor of hearing loss?

Age (about 25% of people 65-74, 50% over 75)

What is conductive hearing loss?

Outer or middle ear problem (wax, otitis media, perforation, otosclerosis); pt speaks softly and may hear better in noise

What is sensorineural hearing loss?

Inner ear or CN VIII problem (aging, noise, Ménière, ototoxic drugs); can hear sound but can't understand speech

What do hearing aids do in sensorineural loss (her slides)?

Make sound louder but not clearer