Cataracts Flashcards
How is energy produced in the lens?
Via anaerobic processes
When new lens cells are formed, where do they go?
Around the outside, and envelope all the old cells
Where do metabolites accumulate in the lens?
In the compact spaces of the inner lens
Does a healthy lens have a high or low level of intracellular Ca++?
Low
If there is too much or too little Ca++ in the lens, what is prone to occur?
Cataract formation
What reduced protein aggregation in the lens, and how?
Mini-chaperones block amyloid fibril formation, sequester metal ions, stabilize mutant proteins and prevent apoptosis
Where are the oldest cells of the lens?
In the center - nuclear and inner cortical layers
Which type of cataracts is associated with a myopic shift?
Nuclear Sclerosis
What is the #1 cause of blindness worldwide?
Cataracts
What percentage of cataracts are genetically determined?
50%
What are the other causes of congenital cataracts?
Intrauterine infections (rubella, varicella, toxoplasmosis), metabolic disorders, trauma, inflammatory ocular disease
What are the four congenital cataract types?
Lamellar/zonular, pulverulent (dots on embryonic/fetal nucleus), cerulean (blue dot), sutural
What are the three types of age-related cortical cataracts?
Polar, capsular/subcapsular, cuneiform (spoke-like)
Why is chronic diarrhea a common cause of cataracts?
Acidosis
What occurs in the formation of a nuclear cataract?
Increase in insoluble protein, chromophores, density, and refractive index
Why do cortical cataracts often start inferiorly?
That is where UV generally does the most damage
What might occur with a morgagnian cataract?
Lens protein may leak out and trigger a non-granulomatous inflammatory response and endophthalmitis, causing accumulation of macrophages and protein in the TM, elevating the IOP potentially causing glaucoma
When does a PSC tend to occur in relation to NS or cortical cataracts?
At a younger age
What conditions are associated with PSC?
Diabetes, steroid use, inflammation (uveitis), trauma, choroquine, retinal degeneration (RP), radiation, atopic dermatitis, neurofibromatosis
What cataracts are associated with atopic dermatitis?
PSC, ASC - 10% develop rapid cataracts, including anterior “shield” cataract
What cataracts are associated with diabetes?
PSC, snowflake cortical (is the “classic” diabetic cataract)
What cataract is associated with myotonic dystrophy?
Christmas tree cortical cataract - probably related to cysteine levels and breakdown of crystallins induced by high Ca levels
