Cataracts I

Question 1

Define cataracts and developmental cataract

Answer 1

• any congenital or opacity in the lens, irrespective of the effects on vision.
• can cause visual impairement
• Developmental cataract: congenital or formed early in life, usually doesn’t interfere with vision.

Question 2

Describe the structure of lens:

(percentage water, percentage solid, majority of solids, high/low concentrations of K+ and Na+?, what causes it to remain clear?)

Answer 2

• 65% water, 35% solids
• 85% of solids soluble alpha and beta crystalline fibres from cortex
• High concentration of potassium
• low concentration of sodium
• proteins determine whether or not lens remains clear

Question 3

What embryological structure is lens made from (ectoderm, neuroectoderm?), and what vessel nourishes the lens during embryolic stage? (hyaloid artery)

Answer 3

• made from surface ectoderm

- nourished by tunica vasculosa lentis

Question 4

Describe a congenital nuclear cataract

What it is, where is it located, what does it develop from, does it affect vision?

Answer 4

• tiny white dot at the center of lens
• formed by loose epitrichial cells caught during lens vesicle formation
• rarely affects vision

Question 5

Describe a anterior pole (pyramidal) cataract

When does it form, where is it located, what does it develop from, does it affect vision?

Answer 5

• forms in 4th week as lens pinches off ectoderm
• opacity at front surface of lens
• pyramidal shape with apex pointing outward into anterior chamber
• no vision impairment

Question 6

Describe umbilical cataract

When does it form, where is it located, what does it develop from, does it affect vision?

Answer 6

• forms in 4th week, posterior epithelial cells move forward to become primary lens fibers
• failure to migrate leads to normal nucleus never forming

Question 7

Describe axial fusion cataract

When does it form, where is it located, what does it develop from, does it affect vision?

Answer 7

• lens fibers due while migrating forward
• opacity occurs in the anterior/posterior direction
• appears in multiple layers of lens

Question 8

Describe sutural cataract

How does it form, where is it located, what is the extra space filled with

Answer 8

• forms when lens does not meet properly

- extra space is filled with albuminoid substance

Question 9

You perform SLE on a patient and see a white dot at the center of the lens but does not appear to affect vision. What is the most likely type of cataract?

A. Congenital Nuclear Cataract
B. Anterior Pole Cataract
C. Umbilical Cataract
D. Axial fusion Cataract
E. Sutural Opacities

Answer 9

A. Congenital Nuclear Cataract

Question 10

You perform SLE on a patient and see a pyramid shaped opacity on the front surface of the lens capsule. What is the most likely type of cataract?

A. Congenital Nuclear Cataract
B. Anterior Pole Cataract
C. Umbilical Cataract
D. Axial fusion Cataract
E. Sutural Opacities

Answer 10

B. Anterior Pole Cataract

Question 11

You perform SLE on a patient and see an collapsed opaque lens without a nucleus. What is the most likely type of cataract?

A. Congenital Nuclear Cataract
B. Anterior Pole Cataract
C. Umbilical Cataract
D. Axial fusion Cataract
E. Sutural Opacities

Answer 11

C. Umbilical Cataract

Question 12

You perform SLE on a patient and see opacities occuring in the anterior posterior direction (from lens fiber death) across many layers. What is the most likely type of cataract?

A. Congenital Nuclear Cataract
B. Anterior Pole Cataract
C. Umbilical Cataract
D. Axial fusion Cataract
E. Sutural Opacities

Answer 12

D. Axial fusion Cataract

Question 13

You perform SLE on a patient and see that the lens fibers do not meet properly with gaps filled with albuminoid substance. What is the most likely type of cataract?

A. Congenital Nuclear Cataract
B. Anterior Pole Cataract
C. Umbilical Cataract
D. Axial fusion Cataract
E. Sutural Opacities

Answer 13

E. Sutural Opacities