Cornea

Question 1

Four quantitative videokeratographic indices for screening keratoconic patients

Answer 1

1. central corneal power >47.2 D
2. inferior-superior dioptric asymmetry >1.2 D
3. Sim-K astigmatism >1.5 D
4. skewed radial axes >21°

Question 2

Why is immune status important when treating HSV/HZV?

Answer 2

Valacyclovir, a pro-drug of acyclovir, can cause TTP/HUS in severely immuno-compromised patients such as those with AIDS; thus, it must be used with caution if the immune status is unknown.

Question 3

Minimum normal inferior forniceal depth

Answer 3

> 8 mm

Question 4

Define keratomalacia

Answer 4

softening and necrosis of the cornea associated with vitamin A deficiency.

Question 5

Ddx of peripheral K ulcers

Answer 5

1. Mooren’s
2. staph marginal
3. terrien’s
4. PUK
5. Fuchs superficial marginal keratitis
6. HSV epithelial keratitis

Question 6

Bacteria that can penetrate intact epithelium

Answer 6

“No Hard or Soft Contact Lenses”

Neisseria (both types), haemophilus aegypti, shigella, corynebacterium, listeria

Question 7

Types of HSV keratitis and treatment

Answer 7

Primary:
1. Unilateral blepahroconjunctivitis (bilateral in kids, immunosuppressed, atopes) – self limited, but can use po antivirals

Recurrent

1. Epithelial keratitis (dendritic, geographic): po or topical antiviral +/- debridement
2. Stromal keratitis s ulceration- prophylactic dose po antiviral, topical steroid
3. Stromal keratitis c ulceration-tx dose po antiviral, topical steroid
4. Endothelial (Disciform) keratitis- tx dose po antiviral, topical steroid

Question 8

HEDS Study Conclusions

Answer 8

1. topical steroids effective in stromal keratitis when combined c trifluridine prophylaxis
2. oral ACV provides no addt’l benefit in pts with stromal keratitis tx c topical steroids and trifluridine
3. study terminated early, but trend toward benefit of oral ACV in HSV Iridocyclitis
4. in epi keratitis tx’ed c trifluridine, oral ACV provides no addt’l benefit in dec risk of stromal keratitis or iritis
5. oral ACV dec risk of recurrent heretic dz esp in pts with stromal dz
6. H/o epi keratitis not a RF for recurrent epi dz, but stromal keratitis inc risk of recurrent stromal keratitis

Question 9

Filamentous fungi

Answer 9

Aka molds –> form hyphae

Septate: aspergillus, curvularia, fusarium, penicillium, phialophora, paecilomyces

Non-septate: mucor

RF: trauma c vegetable matter, scl wear

Question 10

Yeasts

Answer 10

Aka non-filamentous and don’t form hyphae

Candida
Cryptococcus

RFs: scl wear, topical steroids, PED, immunocompromise

Question 11

Dimorphic fungi

Answer 11

Non-filamentous –> no hyphae

Histoplasma
Blastomyces
Coccidioides

Question 12

Post refractive sx historic method for IOL calls

Answer 12

Ave preoperative Ks
Calculate SE for pre nd postoperative mrx
Add/subt to ave preoperative k depending on whether LASIK was myopic or hyperopia (see OQ #6, 1/28)

Question 13

Axis of greatest astigmatism in pellucid

Answer 13

180 (nasal/temp thinning lead to ATR cyl –> crab claw)

Question 14

Gene defect in Schnyder’s dystrophy

Answer 14

UbiA prenyltransferase domain-containing protein 1 (UBIAD1)

Question 15

Ts of Terrien’s

Answer 15

T: Thinning of the cornea
T: Top (superior)
T: Traversing pannus over area of thinning
T: Thirties
T: Can take Turns (mostly unilateral but can be bilateral)
T: Treatment: Transplantation (cresent shaped lamellar) if perforation occurs

Question 16

Corneal side FX of topical NSAIDs

Answer 16

MELT and also PEE

Question 17

K thickness above which endothelial cell damage is likely

Answer 17

640 microns

Question 18

Protein defect in Reis-Buckler

Answer 18

Keratoepithelin

Question 19

DDX acute and chronic follicular conjunctivitis

Answer 19

Acute: Adeno hardly happens to careful nuns
Adeno, HSV, hemorrhagic, chlamydia, Newcastle (Neisseria?– not according to Friedman #8)

Chronic: Passing tough tests means mostly late cramming
Parinauds, trachoma, toxic, molluscum, moraxella, Lyme, chlamydia

Question 20

DDX verticillata

Answer 20

Amiodarone, indomethacin, chloroquine, chlorpromazine

Fabrys

Question 21

Eye findings in Fabry’s

Answer 21

Vortex keratopathy
Tortuous/telangiectasia vessels of conj AND retina
Granular lens opacities

Question 22

Describe ocular vs oculodermal melanocytosis

Answer 22

Ocular: congenital blue Nevus of episclera; more common in whites; 10% risk of ipsilateral glc and 1/400 risk of uveal melanoma
Oculodermal melanocytosis: ocular melanocytosis + peri ocular cutaneous melanocytosis; more common in AA/Asians, but malignant transformation occurs almost exclusively in whites

Question 23

Gland type:
Krause
Wolfring
Zeis
Meibomian
Moll

Answer 23

Krause: eccrine; lacrimal
Wolfring: eccrine; lacrimal
Zeis: holocrine; sebaceous (a/w cilia)
Meibomian: holocrine; sebaceous
Moll: apocrine

Question 24

DDX K crystals

Answer 24

K dystrophy (macular, granular, lattice dystrophy, Schnyder), Bietti’s, ciloxan deposits, Strep Viridans (ICK), cystinosis, multiple myeloma, and monoclonal gammopathy

Question 25

Neomycin K changes

Answer 25

Wessely ring/periph k infiltrate

Question 26

Criteria for K graft tissue

Answer 26

Endo count > 2000/mm3, age 2-70, death to pres time < 18 hrs

Question 27

Verticillata DDX

Answer 27

FACTS IN identifying whorls in the corneal (corneal verticillata): 
F: Fabrys 
A: Amiodarone (m/c) 
C: chloroquine (hydroxychloroquine)/chlopromazine 
T: Tamoxifen 
S: Subconjunctival gentamicin 
I: Ibuprofen/ Indomethacin 
N: Naproxen

Question 28

Urrets-Zavalia syndrome

Answer 28

Fixed dilated pupil and sector iris atrophy p PKP

Question 29

Tx of tyrosinemia

Answer 29

Restrict dietary tyrosine and phenylalanine

Due to defect of tyrosine aminotransferase; In the DDX of pseudodendrite