Lenticular Disorders

Question 1

Associations with ectopia lentis

Answer 1

Trauma
Marfans(ST)
Homocystinuria(IN)
Ectopia lentis et pupillae (displaced in the opposite direction from slit pupil) — AR

Question 2

Inheritance of congenital cataracts

Answer 2

AD

Bilateral

Question 3

What complicates IOL calculation in post-myopic refractive surgery patients?

Answer 3

1. Radius error
   - Estimates in corneal power are made using calculations from outside the radius of correction, so measurements will not account for the more-oblate shape of the cornea and overestimate the curvature
   - This is not affected by RK
   - Leads to hyperopic surprise
2. Keratometer index error
   - The Gullstrand Ratio = ratio of anterior to posterior radii of curvature
   - Gullstrand ratio is altered in refractive
   - Leads to hyperopic surprise
3. Formula error
   - 3rd generation formulas predict effective lens position via corneal power and AL; however the flattened curve would underestimate AC depth
   - Hyperopic surprise
   - Better to use Haigis, Haigis-L