Lens Pathophysiology (F) Flashcards
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?
Peter’s anomaly
What physiological factors can lead to cataracts?
- Disruption of lens structure
- Increase in protein aggregation
- Cytoplasmic phase separation
- Brunescent
What are the three different classifications of cataracts based on the region they are in?
- Nuclear
- Cortical
- Posterior subcapsular
- Mixed
What are the general risk factors associated with cataracts?
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)
What are the general risk factors associated with cataracts?
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)
What type of cataracts are thinner lenses associated with?
cortical cataracts
What type of cataracts are thicker lenses associated with?
nuclear cataracts
What is the most likely reason for age-related nuclear cataracts?
increased oxidative damage to lens proteins and lipids due to a failure in glutathione-dependent reduction pathways
What is the most likely reason for age-related nuclear cataracts?
increased oxidative damage to lens proteins and lipids due to a failure in glutathione-dependent reduction pathways
When the α-crystallin is overwhelmed and cannot maintain its tasks what happens?
β- and γ-crystallin become reduced producing insoluble crystallin aggregates
Which lens fibers are more susceptible to oxidative damage?
central fibers
What quadrant of the lens do age-related cortical cataracts usually form?
inferior/nasal quadrant
In cortical cataracts when opacities extend along fibers in a group what are they called?
“cortical spokes”
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
- more severe
- Thin lens; greater sunlight exposure; poorly controlled diabetes
- after accommodative function ceases
- Cytoplasmic calcium levels
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
- more severe
- Thin lens; greater sunlight exposure; poorly controlled diabetes
- after accommodative function ceases
- Cytoplasmic calcium levels
What type of cataract is light scattering in a cluster of swollen cells at the posterior pole just beneath capsule?
posterior subcapsular cataracts
What is the cause of posterior subcapsular cataracts?
aberrant migration or differentiation of lens epithelial cells or swelling of posterior ends of fibers along the suture plane
What happens in the lens in response to hyperglycemia?
lens cells will generate sorbitol via aldose reductase
How are cataract affect lenses removed from the eye?
peripheral corneal incision and a phacoemulsification instrument
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?
posterior capsular opacification (PCO)
What is the formation of an opaque plaque near center of lens epithelium?
Anterior polar cataract (APC)
Intrauterine infection of pregnant women can cause what congenital syndrome in the newborn?
rubella virus
Intrauterine infection of pregnant women can cause what congenital syndrome in the newborn?
rubella virus
What causes the cataract for patients with rubella virus?
failure of organelle degradation
