Chronic Vision Loss

Question 1

Causes of chronic vision loss

Answer 1

Progressive vision loss: Cataract, AMD, Glaucoma, Amblyopia
Acute/chronic: Diabetic retinopathy
Misc: Refractive error, dry eye, cornea

Question 2

Cataract

Answer 2

Lens clouding
33% of all blindness
Prevalence increases w/ age (typically 60s-80s)

Question 3

Cataract Sx

Answer 3

Progressively blurry vision (typically over years)
Halos, Glare
Sx tend to be worse @ night (increasingly worse night driving)

Question 4

Nuclear sclerosis cataract

Answer 4

Center of lens progressively clouds w/ age
Possible associations: UV, diet, systemic disease, free radicals
Myopic shift can occur d/t cataract

Question 5

Posterior subcapsular cataract

Answer 5

Clouding of posterior lens aspect
Usually small/thin but greatly affects vision
Ass w/ dibetes, steroid usage
Can develop quickly

Question 6

Cortical cataract

Answer 6

Cortex changes
Usually spoke-like
Rarely affect vision unless in visual axis (as they become more progressed)
May cause more glare

Question 7

Miscellaneous cataracts

Answer 7

Traumatic (post-surgical or other)

Congenital (e.g. metabolic disorder)

Question 8

Cataract Tx

Answer 8

Extraction (If functionally significant)
Generally, when vision < 20/40, glare, halos (difficult to drive, read, etc.)
Do the benefits of extraction outweigh risks? If not, don’t perform

Question 9

Cataract Extraction

Answer 9

Small incision @ edge of cornea
Break cataract w/ phacoemulsification & suction out
Leave edge of capsule to attach new IOC lens
Feel grittiness in eye at first, goes away in a couple days
Typically under conscious sedation, occasionally paralyze EOM, rarely under full anesthesia

Question 10

Age-related macular degeneration (AMD)

Answer 10

Blurred/no vision in center of visual field
1.75 million in US
LEADING CAUSE OF IRREVERSIBLE BLINDNESS IN DEVELOPED COUNTRIES
Ass w/ family hx, caucasian, smoking, age

Question 11

Dry/non-neovascular AMD

Answer 11

80-90%
Drusen (yellow deposits) formation
Loss of retinal pigment epithelium –> atrophy of photoreceptors (geographic atrophy)

Question 12

Wet/neovascular AMD

Answer 12

10-20%
Neovascular membranes form under retina
New vessels leak, fluid accumulates in retina

Question 13

AMD Sx

Answer 13

Blurry vision centrally
Peripheral vision spared
May be distorted (Amsler grid)

Question 14

AMD Dx

Answer 14

Fluorescein angiography (ID leaky vessels, wet vs. dry)
Optical coherence tomography/OCT (Cross section of macula, ID fluid under retina)

Question 15

AMD Tx

Answer 15

Prevention - Don’t smoke, AREDS2 vitamins for dry AMD (Vitamin C, Vitamin E, Lutein, Zeaxanthin, Zinc) reduce pt. going from dry –> wet by 25%

Neovascularization Tx: Anti-VEGF injections to prevent new vessel growth. Monthy-ish

Question 16

Glaucoma

Answer 16

Death of retinal ganglion cells
High IOP does NOT = glaucoma
Loss of peripheral vision, slow development of tunnel vision (Rarely blinds)
SLOW
6-8x more common in Blacks
Ass. w/ advanced age, family hx

Question 17

Glaucoma Pathophysiology

Answer 17

Unknown.
Damage to cell bodies or axons primarily?
Ocular hypertension, low tension glaucoma

Question 18

Types of Glaucoma

Answer 18

Primary open angle
Acute angle closure
Chronic angle closure
Secondary

Question 19

Primary open angle glaucoma

Answer 19

Trebecular meshwork open and functioning

Fluid not draining fast enough (increased humor production) and pressure increased

Question 20

Acute angle closure glaucoma

Answer 20

Trebecular meshwork closed off

Iris too close to cornea/closes off

Question 21

Patient ed. w/ glaucoma tx

Answer 21

Pt. quit glaucoma meds and say they feel great, glaucoma isn’t getting worse.

BUT –> only advanced visual field defects are noticeable

SO –> meds are preventing or slowing worsening of glaucoma, even if “not noticeable”

AND –> if you stop meds, glaucoma will slowly get worse

Question 22

Glaucoma Exam

Answer 22

Increased cup:disc ratio often seen (but not always)

Question 23

Glaucoma Dx

Answer 23

Increased IOP, cup/disc ratios

Decreased visual fields, retinal nerve fiber layer on OCT

Question 24

Glaucoma Tx

Answer 24

Drops! Prostaglanding, beta-blocker, alpha agonist, carbonic anhydrase inhibitor

Laser directly into trabecular meshwork (decreases pressure and opens drainage); Similar to adding a drop

Surgery: (Trabeculectomy, Tube (possibly valved), Mini-shunt) - allows drainage, works well, but can fall out, needs lots of follow-u and may still need drops

Question 25

Why is there poor med adherence w/ glaucoma drops?

Answer 25

Complicated and confusing. Often end up w/ one drop qday, one BID, one TID w/ different dosing in different eyes.
All this can be hard to keep straight.

Question 26

Diabetic retinopathy

Answer 26

Vision loss from macular edema, retinal detachment, vitreous hemorrhage

Question 27

Diabetic retinopathy Tx

Answer 27

Focal laser/panretinal photocoagulation
Can’t see from lasered spot, but preserves central vision
BEST is PREVENTION: Good diabetic control

Question 28

Refractive Error

Answer 28

Common cause of blurry vision
Presbyopia (40s) - hardening of lens
Myopic shift (become more near sighted)
Reading glasses? Prescription adjustment?

Question 29

Dry Eye Syndrome

Answer 29

Common cause of blurry vision
Fluctuating vision - Blurry sometimes, blinks, goes away.
Worse in winter, with extended reading and computer use

Question 30

Dry Eye Tx

Answer 30

Artificial Tears w/ preservative up to 4x/day
>4x/day? Artificial Tears w/o preservative (use as much as you want)

Plugs option after AT –> reduces tear drainage but prefer AT. Plug should fall out on own.