Vitreous

Question 1

Vitreous size? In Newborn and Adult?

Answer 1

80%
Newborn: 10.5mm
Adult: 16.5mm

Question 2

Vitreous components

Answer 2

98% water

collagen, GAGs

Question 3

Collagen types

Answer 3

75% Type II
10% Type V
10% Type XI

Question 4

Which artery penetrates and allows for more fibrillar material to fill the “space?” What is this space?

Answer 4

Hyaloid artery

Primary vitreous

Question 5

The size of the vitreous cavity increases and the hyaloid vascular system regresses into the…

Answer 5

secondary vitreous

Question 6

What canal is made by the disappearance of the hyaloid artery?

Answer 6

Cloquet’s canal

Question 7

A tube of primary vitreous surrounded by secondary vitreous running from retrolental space to the optic nerve.

Answer 7

Cloquet’s canal

Question 8

tertiary vitreous

Answer 8

Zonules of the lens: suspensor fibrils

Question 9

Zonules are developed from then….

Answer 9

fibrillary material

Question 10

Cortex

Answer 10

outermost part of the vitreous

Question 11

Base

Answer 11

three dimensional zone extending from 2mm anterior to 3mm posterior to the ora serrata; it is several mm thick.

Question 12

Where are collagen fibrils densely packed?

Answer 12

Base

Question 13

Internal Limiting Membrane

Answer 13

ILM
1-3 microns thick
IV collagen ad proteoglycans; considered basal lamina of the Mueller cells.

Question 14

Where is vitreous cortex attached to the ILM?

Answer 14

Vitreous base
optic disc (Weiss ring)
vessels
area around foveola

Question 15

Vitreous vs. Blood

Answer 15

increase Ascorbate
Increase glycoaminoglycans
increase protein (collagen)
decrease K
decrease glucose

Question 16

substances move via…

Answer 16

bulk flow or diffusion (fluorescein)

Question 17

True/False:

Bulk flow plays a significant role for distribution of low molecular weight substances in the vitreous

Answer 17

False

Question 18

Liquefacation of the gel structure

Answer 18

synchysis (replaced with aqueous lacunae)

Question 19

Insoluble proteins produced by a covalent bond between an amino group and glucose

Answer 19

Maillard Rxn

Question 20

The central degeneration is large and causes a collapse that causes the cortex to sink to the center of the vitreous body.

Answer 20

Posterior Vitreous Detachment (PVD)

Question 21

1st step in the retinal tear process?

Answer 21

rhegamatogenous retinal detachment

Question 22

Increased passive permeability and decreased outward active transport may…

Answer 22

lead to macular edema

Question 23

What happens to oxygen tension in diabetic patients after a vitrectomy?

Answer 23

Oxygen transport increases; decreasing retinal neovascularization and macular edema.

Question 24

What pathological conditions interfere with transparency?

Answer 24

synchysis scintillations
asteroid degeneration
hemorrhages
inflammatory material
fibrous tissue
regression of the hyaloid artery