Lens Pathophysiology (F)

Question 1

What is a failure of embryonic lens vesicle to separate from the prospective cornea forming a lens “stalk” that is connected to the cornea and persists into the mature eye?

Answer 1

Peter’s anomaly

Question 2

What physiological factors can lead to cataracts?

Answer 2

1. Disruption of lens structure
2. Increase in protein aggregation
3. Cytoplasmic phase separation
4. Brunescent

Question 3

What are the three different classifications of cataracts based on the region they are in?

Answer 3

1. Nuclear
2. Cortical
3. Posterior subcapsular
4. Mixed

Question 4

What are the general risk factors associated with cataracts?

Answer 4

Age
Lower socioeconomic status/lower education
Sex: Women are at increased risk for most kinds
Smoking
High alcohol consumption
Dark iris color
Exposure to anti-inflammatory steroids (increased risk for posterior subcapsular)
Exposure to ionizing radiation (increased risk for posterior subcapsular)
Lens size (thickness)

Question 5

What are the general risk factors associated with cataracts?

Answer 5

Age
Lower socioeconomic status/lower education
Sex: Women are at increased risk for most kinds
Smoking
High alcohol consumption
Dark iris color
Exposure to anti-inflammatory steroids (increased risk for posterior subcapsular)
Exposure to ionizing radiation (increased risk for posterior subcapsular)
Lens size (thickness)

Question 6

What type of cataracts are thinner lenses associated with?

Answer 6

cortical cataracts

Question 7

What type of cataracts are thicker lenses associated with?

Answer 7

nuclear cataracts

Question 8

What is the most likely reason for age-related nuclear cataracts?

Answer 8

increased oxidative damage to lens proteins and lipids due to a failure in glutathione-dependent reduction pathways

Question 9

What is the most likely reason for age-related nuclear cataracts?

Answer 9

increased oxidative damage to lens proteins and lipids due to a failure in glutathione-dependent reduction pathways

Question 10

When the α-crystallin is overwhelmed and cannot maintain its tasks what happens?

Answer 10

β- and γ-crystallin become reduced producing insoluble crystallin aggregates

Question 11

Which lens fibers are more susceptible to oxidative damage?

Answer 11

central fibers

Question 12

What quadrant of the lens do age-related cortical cataracts usually form?

Answer 12

inferior/nasal quadrant

Question 13

In cortical cataracts when opacities extend along fibers in a group what are they called?

Answer 13

“cortical spokes”

Question 14

For cortical cataracts is the damage to cells more or less severe? 1. What are the risk factors? 2. When do these normally occur? 3. What levels are abnormally high? 4

Answer 14

1. more severe
2. Thin lens; greater sunlight exposure; poorly controlled diabetes
3. after accommodative function ceases
4. Cytoplasmic calcium levels

Question 15

For cortical cataracts is the damage to cells more or less severe? 1. What are the risk factors? 2. When do these normally occur? 3. What levels are abnormally high? 4

Answer 15

1. more severe
2. Thin lens; greater sunlight exposure; poorly controlled diabetes
3. after accommodative function ceases
4. Cytoplasmic calcium levels

Question 16

What type of cataract is light scattering in a cluster of swollen cells at the posterior pole just beneath capsule?

Answer 16

posterior subcapsular cataracts

Question 17

What is the cause of posterior subcapsular cataracts?

Answer 17

aberrant migration or differentiation of lens epithelial cells or swelling of posterior ends of fibers along the suture plane

Question 18

What happens in the lens in response to hyperglycemia?

Answer 18

lens cells will generate sorbitol via aldose reductase

Question 19

How are cataract affect lenses removed from the eye?

Answer 19

peripheral corneal incision and a phacoemulsification instrument

Question 20

What is the complication of cataract surgery where lens epithelial cells remaining after surgery can differentiate into a mass of fiber like cells around capsular equator and could form lentoid like bodies?

Answer 20

posterior capsular opacification (PCO)

Question 21

What is the formation of an opaque plaque near center of lens epithelium?

Answer 21

Anterior polar cataract (APC)

Question 22

Intrauterine infection of pregnant women can cause what congenital syndrome in the newborn?

Answer 22

rubella virus

Question 23

Intrauterine infection of pregnant women can cause what congenital syndrome in the newborn?

Answer 23

rubella virus

Question 24

What causes the cataract for patients with rubella virus?

Answer 24

failure of organelle degradation