Cornea 2

Question 1

Senile furrow degeneration

Answer 1

Appearance of thinning peripheral cornea in clear space between arcus and limbus. Not usually actual thinning. Totally benign.

Question 2

Corneal farinata

Answer 2

suble dot-shaped and comma shaped opacities within the deep stroma that are age related (possible lipofuscin?) and have no clinical or visual significance.

Question 3

What ELISA test can be performed to help in diagnosis of macular corneal dystrophy?

Answer 3

keratan sulfate

Question 4

What are the types of hypolipoproteinemia syndromes that can results in corneal clouding?

Answer 4

LCAT (lecithin-cholesterol acyltransferase) deficiency
Tangier disease
Fish eye disease

Question 5

Corneal dystrophies are AD EXCEPT which ones are AR?

Answer 5

Macular, Lattice type 3 only, gelatinous, and CHED2 (has nystagmus) are all AR!

Question 6

What is the vision usually like in Meesman’s CD?

Answer 6

Good, all though tiny epithelial vesicles do affect the central cornea they are ususually not VS.

Question 7

Reis-Bucklers’ and Thiel-Behnke’s is dystrophy of what layer of the cornea?

Answer 7

Bowmans

Question 8

Central Cloudy (Francois) dystrophy is similar to what benign corneal finding?

Answer 8

Crocodile shagreen

Question 9

Which corneal dystrophy has endothelium that behaves like epithelium forming multiple layers and occasional migration to the angle causing glaucoma? What other ocular disease is this dystrophy most similar to?

Answer 9

Posterior polymorphous; ICE syndrome

Question 10

Fuchs superficial marginal keratitis is similar to what condition but happens in kids?

Answer 10

Terrien’s marginal degeneration

Question 11

PTK can be used for pathology how deep?

Answer 11

Limited to 1/3 of stroma

Question 12

What is the most common cause of mucin deficiency?

Answer 12

Vit A deficiency

Question 13

What is characteristic of congenital stromal corneal dystrophy (CSCD)?

Answer 13

Diffuse clouding of the central cornea with whitish flakes

Question 14

Alkaptonuria has what characteristic ocular surface finding?

Answer 14

pigmented conjunctiva at or near horizontal muscle insertions

Question 15

Staph marginal infiltrates is what type of hypersensitivity reaction?

Answer 15

Type IV

Question 16

Fleck corneal dystrophy has flecks in what part of the cornea?

Answer 16

stroma

Question 17

How thick is eyelid skin?

Answer 17

0.5mm near margin and 1mm at orbital rim

Question 18

How long does it take for cilia to grow back when cut? When pulled out?

Answer 18

2 weeks; 2 months

Question 19

What is a normal blink rate in adults?

Answer 19

15/min

Question 20

What is the horizontal and vertical diameters of the adult cornea?

Answer 20

11-12; 10-11

Question 21

What is the average radius of curvature of the adult cornea? What is the average dioptric power?

Answer 21

7.8; 43.25

Question 22

How thick is the average corneal epithelial layer?

Answer 22

50 microns

Question 23

What type of collagen is the corneal stroma composed of?

Answer 23

I, V, VI: 1+5=6

Question 24

What mechanisms help in maintaining the hydration status of the cornea?

Answer 24

1. Active transport

2. Swelling pressure produced by negatively charged glucosaminoglycans

Question 25

What is a normal endothelial cell density?

Answer 25

2000-3000 cc/mm2

Question 26

What type of collagen is the sclera composed of?

Answer 26

Type 1 primarily

Question 27

What are 1. Basic secretion test; 2. Schirmer 1 test; 3. Schirmer 3 test? What are cut offs for abnormal?

Answer 27

1. TOPICAL anesthetic followed by paper strip; less than 3mm is abnormal (5 min) 2. No anesthetic followed by paper strip; less than 5.5 is abnormal (5 min) 3. TOPICAL anesthetic followed by paper strip AND nasal irritation; less than 15 is abnormal (2 min)

Question 28

What amount of K edema starts to result in D-folds? Microcystic epithelial edema?

Answer 28

Greater than 10% thickness increase; over 700 microns

Question 29

What are the different zones of the cornea?

Answer 29

1. Central zone: 1-2 mm 2. Paracentral zone 3-4 mm from central zone 3. Peripheral zone between paracentral and limbal 4. Limbal zone