1 Crystalline Lens

Question 1

Which curvature (anterior or posterior) of the crystalline lens is steeper?

Answer 1

Posterior!! 5-8mm ROC

Anterior 8-14mm Radius of Curvature. Smaller ROC

Question 2

At birth, lens diameter is 6.5mm, adulthood it’s 10mm.. the diameter doesn’t increase a lot with age like ________, which increases ____mm/year

Answer 2

Thickness

0.02mm/year

Question 3

The index of refraction for the lens is ________ due to the ________ distribution of crystallin proteins in the lens fibers

Answer 3

Non-uniform; non-uniform

Question 4

What are the three layers of the crystalline lens from inner to outer??

Answer 4

Elastic capsule

Lens epithelium

Lens fibers

Question 5

What part of the crystalline lens is the thickest in the body around 20 microns?

Answer 5

Elastic capsule

Question 6

What comprises the elastic capsule?

Answer 6

COLLAGEN!!!!!

No elastic fibers in the capsule

Question 7

The lens capsule:

_____ barrier that allows freely permeable low-molecular weight compounds (from aqueous humor)

Makes lens pliable to pull of _________ during accommodation

Answer 7

Diffusion

Zonular fibers

Question 8

What’s the outermost layer of the lens capsule to which the zonules will attach?

Answer 8

Zonular lamella

Question 9

The lens epithelium is a monolayer of many ______cells. They eventually stretch over a lifetime and become _____ shape

Answer 9

Cuboidal

Columnar

Question 10

The lens epithelium does 3 things:

1) proliferates at _______ zone to form lens fibers
2) _____ anterior epithelium transports stuff from ________ to lens interior
3) secretes the ___ ______

Answer 10

Germanative

Central. Aqueous humor

Lens capsule

Question 11

What lens fibers constitute the bulk of the lens? The nucleus moves anteriorly and forms lens bow that gents pushed towards center

Answer 11

Secondary lens fibers

Question 12

Once the fibers have lost their nuclei, organelles of fiber form specialized __________- (alpha and beta) that make up 40% of fiber

Answer 12

Lens crystallins

Question 13

List the four divisions of the lens from anterior lens to posterior lens:

Answer 13

Lens cortex

Adult nucleus

Fetal nucleus

Embryonic nucleus

Question 14

Divisions of the lens:

Which one is Earliest mass at center of lenscomposed of primary lens fibers? Formed at 2 months gestation. Does not increase in size

Which one is Formed before birth. Contains the Y sutures. Does not increase in size

Answer 14

Embryonic nucleus

Fetal nucleus

Question 15

Divisions of the lens:

Which one:
Fibers made between birth and sexual maturation. Increases in size throughout life. They sclerose and become yellow with age.

Which one has Newly formed fibers that contain nuclei and surround adult nucleus?

Answer 15

Adult nucleus

Lens cortex

Question 16

What’s the most common complication of cataract surgery? What can you do to treat it after that happens?

Answer 16

Posterior capsule opacification

YAG laser. Yttrium-aluminum-garnet laser