Ophthalmology

Question 1

the eye exam

Answer 1

*visual acuity
*pupils
*intraocular pressure
*extraocular movements
*physical exam

Question 2

measuring visual acuity

Answer 2

*20/20 is “perfect vision”
*first number = distance (in feet) away from the chart (20 ft in US)
*second number = how far a patient with perfect vision could stand and still read that letter (typically 20-400)
*near card is size adjusted
*check eyes individually

Question 3

pupils (eye exam)

Answer 3

*pupils should be equal, round, and reactive to light
*light shone in one eye should cause BOTH pupils to react symmetrically
*unequal pupil size = anisocoria (can be caused by Horner’s syndrome, CN III palsy, trauma, tonic pupil, meds)
*irregular pupils usually secondary to trauma
*nonreactive pupils

Question 4

causes of miotic (small) pupils

Answer 4

older age
opiates
clonidine
organophosphates
pilocarpine

Question 5

causes of mydriatic (dilated) pupils

Answer 5

younger age
cocaine
nasal vasoconstrictors
scopolamine patches

Question 6

red reflex

Answer 6

*red light reflection seen in ophthalmoscopic examination of the eye
*should be checked in infants and children
*abnormal red reflex warrants PROMPT REFERRAL to an ophthalmologist
*possible causes include cataract, strabismus, retinoblastoma

Question 7

intraocular pressure

Answer 7

*normal = 8-22 mmHg
*high intraocular pressure can indicate glaucoma

Question 8

emmetropia

Answer 8

*no refractive error (normal vision)
*distance light rays are focused perfectly on the retina
*for near vision, accommodative reflex causes lens to thicken and focus light on retina

Question 9

refractive error

Answer 9

*light does not focus perfectly on retina
*due to the size (axial length) or shape (corneal curvature) of eye, and focusing power of lens
*important parts/measurements:
-length of eye
-curve of cornea
-flexibility, density, and shape of lens

Question 10

presbyopia

Answer 10

*old eyes
*loss of accommodation associated with normal aging
*near vision becomes out of focus
*correctable with reading glasses or bifocal

Question 11

accommodation

Answer 11

young lenses can change shape to focus near light rays on retina

Question 12

myopia

Answer 12

*nearsightedness
*far away is blurry, close up is clear
*light rays from the distance focus IN FRONT of retina
*eye is too long
*typically gets worse with aging in children (eye continues to grow)
*corrected with a MINUS prescription (concave lens)

Question 13

hyperopia

Answer 13

*farsightedness
*far away clearer than up close
*light rays from distance focus BEHIND the retina
*the eye is too short/small
*most kids are hyperopic but can still see clearly due to lens accomodation
*correct with PLUS prescription (convex lens)

Question 14

astigmatism

Answer 14

*cornea is not spherical
*light rays do not create a single, sharp focus
*can occur with nearsightedness or farsightedness
*correctable with glasses/contacts

Question 15

viral conjunctivitis

Answer 15

*most common cause of infectious conjunctivitis
*conjunctival infection, mucoid discharge, sometimes with URI
*starts unilateral and usually spreads to other eye
*HIGHLY contagious

Question 16

management of infectious conjunctivitis

Answer 16

*strict handwashing, no sharing of linens, non contact lenses for 14 days
*artificial tears, cool compress
*antibiotics typically only required in hyperacute, severe bacterial conjuctivitis

Question 17

corneal abrasion

Answer 17

*epithelial defect in the cornea
*usually heals without treatment in 24-48 hours
*look for associated foreign body (often metal which must be removed)
*associated conjunctival infection (dilated blood vessels on the white of the eye)

Question 18

corneal ulcer

Answer 18

*corneal abrasion plus an underlying suppuration of corneal STROMA
*can be infectious or sterile (neurotrophic)
*usually occurs if a corneal abrasion gets infected
*almost always leads to permanent vision loss

Question 19

cataract

Answer 19

*clear lens (made of crystalline protein) becomes cloudy
*blocks and scatters the light from getting to the retina
*can be congenital or traumatic
*TYPICALLY OCCURS WITH NORMAL AGING (most people will have cataracts at some point if they get old enough)
*tx = surgery

Question 20

causes of cataracts

Answer 20

*normal aging
*UV exposure
*trauma
*diabetes
*corticosteroids

Question 21

cataract surgery

Answer 21

*performed when poor vision is affecting activities of daily living (driving or reading)
*outpatient, fast (10-15 minutes), and typically performed under light sedation (very little recovery time)

Question 22

glaucoma

Answer 22

*damage to the optic nerve, typically arising from HIGH INTRAOCULAR PRESSURE, resulting in permanent vision loss
*usually from INSUFFICIENT DRAINAGE of aqueous fluid
*results in loss of visual field (usually peripheral vision first)
*untreated, can lead to complete, irreversible blindness

Question 23

open-angle glaucoma

Answer 23

*trabecular meshwork is clogged at microscopic level
*causes long-term increase in intraocular pressure
*usually asymptomatic

Question 24

closed-angle glaucoma

Answer 24

*less common than open angle
*iris is pressed against cornea, blocking access to trabecular meshwork
*acute (pain, red eye, nausea, blurry vision)
*could be chronic

Question 25

optic nerve cupping in glaucoma

Answer 25

*the cup gets bigger, the rim gets smaller, due to death of nerve fibers *end result in open or closed angle glaucoma

Question 26

treatment of glaucoma

Answer 26

*goal = lower the intraocular pressure *medications - lower aqueous production or increase aqueous outflow *laser - increase outflow through trabecular meshwork *surgery - increase outflow; usually only if more conservative measures have failed

Question 27

glaucoma medications that increase outflow of aqueous fluid

Answer 27

-prostaglandin analogues (latanoprost) -cholinergic agonists (pilocarpine)

Question 28

glaucoma medications that decrease production of aqueous fluid

Answer 28

-beta blocker (timolol) -alpha agonist (brimonidine) -carbonic anhydrase inhibitor (dorzolamide, acetazolamide) -Rho Kinase inhibitors (netarsudil)

Question 29

glaucoma surgery

Answer 29

*typically only if medications fail *increase outflow by creating a guarded hole "trabeculectomy" from the anterior chamber beneath the conjunctiva *increase outflow by placing a tube shunt from the anterior chamber to beneath the conjunctiva *decrease aqueous production by destroying the ciliary body

Question 30

common retinal disorders

Answer 30

*macular degeneration (dry and wet) *diabetic retinopathy (nonproliferative and proliferative) *retinal detachment

Question 31

risk factors for macular degeneration

Answer 31

-age -race (Caucasian and Scandinavian descent) -family history -UV exposure -tobacco use -HTN

Question 32

dry macular degeneration

Answer 32

*retinal cells die and leave areas of missing, atrophic retina *yellow clumps (drusen)

Question 33

wet macular degeneration

Answer 33

*happens when there is a break in the RPE (retinal pigment epithelium) and blood vessels from choroid grow into the retina and bleed *choroidal or subretinal neovascular membranes are abnormal blood vessels growing under the retina (from the choroid) *driven by VEGF (vascular endothelial growth)

Question 34

treatment for dry macular degeneration

Answer 34

-avoid UV exposure -avoid tobacco -AREDS antioxidant vitamins

Question 35

treatment for wet macular degeneration

Answer 35

*anti-VEGF intraocular injections

Question 36

nonproliferative diabetic retinopathy

Answer 36

*ischemia and blood vessel damage *signs: **microaneurysms, intraretinal hemorrhages, macular edema, exudates, and cotton-wool spots** *tx = control BG and BP, laser, intravitreal injections

Question 37

proliferative diabetic retinopathy

Answer 37

*if vasculopathy is severe enough, retina becomes so ischemic that **vascular endothelial growth factor (VEGF) is released and neovascularization occurs *new, ABNORMAL blood vessels form** -grow on retina and from optic nerve -fragile, so **often bleed** into vitreous *usually causes blindness if untreated

Question 38

treatment for proliferative diabetic retinopathy

Answer 38

*panretinal photocoagulation (PRP): -kills peripheral retina to decrease release of VEGF -sacrifices peripheral retina to preserve central retina -permanent *anti-VEGF injections (nondestructive by effect is short-lived)

Question 39

retinal detachment

Answer 39

*"half of my vision is gone in my right eye" *patient complains of flashing, floaters, or a "curtain coming across vision" *usually, a small tear in peripheral retina that allows fluid into potential space and causes retina to detach

Question 40

strabismus

Answer 40

*misalignment of the eyes *causes: -cranial nerve palsy -congenital/developmental -mechanical (trauma, thyroid eye disease, space occupying lesion in the orbit)

Question 41

esotropia

Answer 41

*strabismus in which one eye is deviated inward (toward the nose) *"crossed eyes"

Question 42

exotropia

Answer 42

*strabismus in which one or both eyes look outward

Question 43

complete CN III palsy

Answer 43

*presentation: affected eye down + out, ptosis, dilated pupil *causes: PCOM ANEURYSM***, ischemia, or trauma

Question 44

abducens palsy

Answer 44

*presentation: affected eye turns inward + unable to abduct *causes: elevated ICP (can be a sign of impending uncal herniation), ischemia, mass

Question 45

strabismus in children

Answer 45

*eye misalignment *brain suppresses the image from one eye to avoid diplopia *treated with glasses and/or surgery *untreated leads to amblyopia

Question 46

amblyopia

Answer 46

*"lazy eye" *insult to visual system during childhood leads to failure of normal cortical visual development *causes: strabismus, anisometropia, high refractive error, deprivation (cataract, corneal scar, ptosis) *treatment involves treating the underlying problem and patching the good eye to force cortical development of the weaker eye

Question 47

thyroid eye disease

Answer 47

*autoantibodies against thyroid receptors (Grave's disease) activate orbital fibroblasts *enlargement of extraocular muscles, fatty and connective tissue within orbit *eye retraction, proptosis, conjunctival infection, strabismus, and double vision *compressive optic neuropathy

Question 48

visual field defects are symmetric in both eyes if insult is where?

Answer 48

POSTERIOR to optic chiasm

Question 49

visual field defects in one eye indicate a problem where?

Answer 49

with eye or optic nerve, ANTERIOR to optic chiasm