Vitreous body

Question 1

what is the hyaloid fossa?

Answer 1

saucer-shaped depression in anterior surface for lens

Question 2

What is the vitreous body attached to? (3)

Answer 2

• Neural retina, especially at ora serrata and margin of optic disc
• pars plana of ciliary epithelium
• lens along periphery of hyaloid fossa (v strong in young, weakens with age)

Question 3

a) What is the hyaloid canal?
b) what is it filled with in adult life?
c) What does it contain in fetal life, where does this derive from and what is it’s purpose?
d) when does it disappear?

Answer 3

a) A narrow (1-2mm wide) channel that runs from optic disc to posterior pole of lens
b) liquid
c) hyaloid artery, branch of central retinal artery. Nourishes lens
d) 6 weeks before birth

Question 4

a) What is the vitreous made of? (4)
b) What does it contain
c) where are these greatest in number
d) which cells are thought to be responsible for its production
e) what other type of cell is found in vitreous (v few in number)

Answer 4

a) Hydrogel consisting of 99% water, some salts, soluble proteins and hyaluronic acid
b) network of fine collagen fibrils that form scaffolding and can be seen under polarised light
c) peripheral of vitreous body/cortex
d) hyalocytes (found in periphery)
e) macrophages

Question 5

What is the function of the vitreous body? (4)

Answer 5

1) transmit light
2) contribute slightly to dioptric power of eye
3) supports posterior surface of lens
4) assists in holding neural part of retina against pigmented part

Question 6

What is the retrolenticular space?

Answer 6

A potential space between lens and hyaloid fossa

Question 7

which processes does vitreous undergo with age?

Answer 7

degeneration and liquefaction can –> vitreous detachment