eye problems & surgeries

functions of the eyes

-refraction

-pupillary constriction/dilation

-accommodation

-convergence

refraction

bending of light, determines how we see

emmetropia

perfect/normal refraction

hyperopia

farsightedness, eye does not refract light enough & images converge behind retina

presbyopia

natural condition that happens with age

mypoia

nearsightedness that occurs when the eye overbends the light and images converge in front of the retina

pupillary constriction/dilation

miosis and mydriasis. Eyes should constrict with bright light or close work and dilate with low light or looking at a distance (depends on retina adaptation)

accommodation

ability to maintain a clear image when the gaze is shifted from a distant object to a near object

convergence

the ability to turn both eyes inward and toward the nose at the same time

astigmatism

a refractive error causes by unevenly curved surfaces, especially the cornea, that distort images

age-related eye changes

-visual acuity decreases

-sunken appearance

-arcus senilis

-cornea flattens

-ocular muscles weaken

-lens elasticity is lost, hardens, compacts, forms cataract

-iris & pupil decrease in adaptability to darkness

-color discrimination decreases

-tear production is reduced

exophthalmos

bulging eyes due to thyroid

ptosis

drooping eyelids

enophthalmos

sunken eyes

anisocoria

different sized pupils

snellen chart

eye testing chart with different sized letters

PERRLA

pupils

equal

round

reactive to light &

accommodation

opthalmoscopy

use of an opthalmoscope to view the interior of the eye

tonometry

the measurement of intraocular pressure

●Family history of glaucoma should have this measured one/two times per year

●Normal readings 10 – 20 mmHg

slit lamp

●Patient rests chin and forehead in the instrument to steady the head for the exam. Dr may use eye drops to make abnormalities more visible or to dilate the pupils

●Magnifies the anterior eye structures so that any abnormalities of the cornea, lens or anterior vitreous humor can be seen

corneal staining

●Placing fluorescein or other topical dye into the conjunctival sac and then the eye is view through a blue filter. Noninvasive, performed under aseptic conditions

●The dye will outline any abnormalities such as corneal trauma, presence of foreign bodies, abrasions, ulcers

nutritional suplements for eye health

-vit A

-lutein

-zeaxanthin

-beta carotene

refractive error tx

-glasses

-contact lenses

-lasik eye surgery

cataracts

clouding of the lens, can be present at birth, develop with age, or be traumatic, toxic, associated, or complicated

symptoms: blurred/double vision, decreased color perception, difficulty seeing at nighty, progressive loss of vision, visible opacity of the lens, and absent red reflex

tx: cataract surgery

cataract surgery

preop- consent, eye gtts for 2-4 prior, stop anticoagulants

intraop- opthalamic drugs dilate pupils-> vasoconstriction & paralysis, local anesthetic injected into muscle cone behind the eye, small incision made, infected lens removed & replaced w/ an IOL

postop- antibiotics & steriod ointments asap, expected bloodshot and mild itching. protect eye until healed with activity restrictions, avoid asprin, watch for complications, no driving

activity restrictions for IOP

-lie on non-op side

-no vacuuming

-no sex

-no jogging or dancing

-no bending

-no sneezing, coughing, blowing nose

-no straining w/ BM

-no vomiting

-no restrictive clothing

-no crunchy foods

glaucoma

increased intraocular pressure results in damage to the retina and optic nerve with loss of vision

risk factors: age 40+ black & hispanic, 60+ any race, hx high eye pressure, corneal thinness, abnormality of the optic nerve

IOP

normal range- 10-21 mmHg

measured by tonometry, slit lamp and tonometer

primary open-angle glaucoma POAG

-IOP 22-32 mmHg

-drainage is reduced

-most common

-gradual onset

-foggy vision

-mild eyeache/headache

-later-> halos around lights, tunnel vison

-PERMANENT vision loss

primary angle-closure glaucoma (PACG)

-≥ 30 mm Hg

-drainage is blocked

-sudden onset, quickly leads to blindness

-severe pain & impaired vision

-nausea/vomiting

-medical emergency, can be reversed w/ tx

glaucoma meds- decrease IOP by ↓ production of aqueous humor

adrenergic agonists- brimonidine

beta-adrenergic blockers- betaxolol hydrochoride, timodol

carbonic anhydrase inhibitors- brinzolamide, dorzolamide, •); oral-acetazolamide & methazolamide

glaucoma meds- decrease IOP by ↑ the outflow of aqueous humor

prostaglandin agonists- brimatoprost, latanoprost, travoprost

cholinergic agonists- carbachol, pilocarpine

glaucoma surgery

-laser trabeculoplasty

-trabeculectomy

-iridotomy

-implanted shunt

postop- patch, gtts, activity restrictions, watch for complications

corneal abrasion

scrape or scratch to the cornea

symptoms- pain, reduced vision, phtophobia, eye secretions, purulent drainage

causes- contact lenses, trauma, malnutrition, dry eye syndromes, certain cancer therapies

-fluorescein stain-> patchy areas turn green

infection-> corneal ulceration-> emergency

fluorescein stain

-assesses unknown pain to visualize trauma, contact lens issues, presence of foreign bodies, abrasions, ulcers

-placed in conjunctival sac

-eye viewed though a blue filter

-dye outlines corneal surfaces and turns abnormalities green

keratoconus

-cornea loses shape due to trauma, inherited disorders, or an untrated corneal infection

-causes visual impairment, unfocused images

-tx= surgery- keratoplasty

keratoplasty

-corneal transplant, remove diseased tissue and relace with donor cornea

post-op- antibiotics, eyepatch for a month, activity restrictions, monitor for signs of infection, gtts, no ice on eye

-complications- bleeding, infection, graft rejection

macular degeneration

deterioration of the macula, middle/central vision

dry or wet

dry macular degeneration

-slow/gradual onset

-blockage of retinal capillaries

-central vision declines

symptoms: mild blurring/distortion, night vision declines, reading loss, loss of all central vision

-no cure

-lutein & zeaxanthin

wet macular degeneration

-progresses quickly

-growth of new blood vessels w/ thin walls leak blood & fluid

-distortion of vision

-tx- laser therapy & ocular injections

-can occur at any age

retinal holes, tears & detachments

-often caused by posterior vitreous detachment

symptoms: sudden painless loss of visual field, bright flashes of light, floating dark spots

tx- laser photocoagulation, cryopexy, scleral buckle

scleral buckle

repair retina by placing silicone against the sclera and hold it in place by an encircling band, draining fluid under retina and putting gas or silicone oil inside the eye to promote retinal attachment

post-op- eyepatch, positioning, activity restrictions, no reading, writing, sewing, teach s/s of infection/detachment (sudden reduced visual acuity, eye pain, non-constrictive pupil

foreign body trauma

•May cause abrasions or irritate the cornea &/or conjunctiva

•Corneal staining: examined with fluorescein

•Irrigate with NS to gently remove particles

•Eye patch

laceration trauma

•Requires immediate medical attention

•Sutures (minor in the ED, more complicated with a microscope in the OR)

•Antibiotics

enucleation

○Surgical removal of eyeball

○Ball implant inserted to provide a base for socket prosthesis & ensure cosmetic fit

○Prosthesis is fitted in approximately 1 month