Lecture 8: Vitreous

Question 1

vitreous humor is what type of substance? where does it fill?

Answer 1

Clear, gel-like substance that fills the eye between the lens and retina

Question 2

what is the volume of vitreous humor?

Answer 2

Volume 4 mL = 80% of the volume of the eye

Question 3

what is the largest structure in the eye?

Answer 3

vitreous humor

Question 4

the vitreous humor is a storage area of what?

Answer 4

Storage area of metabolites for the retina and lens

Question 5

the vitreous humor provides a medium for what?

Answer 5

movement of metabolites

Question 6

the vitreous acts as what?

Answer 6

Acts as a shock-absorber due to its viscoelastic properties

Question 7

the vitreous humor transmits and refracts what?

Answer 7

light

Question 8

vitreous humor is composed of 99% what?

Answer 8

water

Question 9

Vitreous humor is the dilution of what?

Answer 9

It is a dilution of salts, soluble proteins, and hyaluronic acid contained within a meshwork of collagen fibers

Question 10

Long non-branching collagen fibers are suspended in what? And what does this stabilize?

Answer 10

a network of hyaluronic acid, which stabilizes the gel structure and conformation of the collagen fibrils

Question 11

The combination of hyaluronic acid and collagen gives the vitreous humor what?

Answer 11

it viscoelastic properties (shock absorber)

Question 12

Hyaluronic acid is believed to maintain what?

Answer 12

the wide spacing between the collagen fibrils

Question 13

what is the anterior boundary of the vitreous humor?

Answer 13

The posterior surface of the lens & Retrozonular portion of the posterior chamber (Canal of Petit)

Question 14

what are the peripherally and posterior boundaries of the vitreous humor?

Answer 14

Pars plana, retina, and optic nerve

Question 15

Weigert’s Ligament (retrolental ligament):

Answer 15

Annular attachment between the posterior lens capsule and anterior vitreous face. Firm attachment, but
weakens with age

Question 16

Space of Berger:

Answer 16

Potential space within the center of Weigert’s ligament because the vitreous and lens are juxtaposed rather than joined.

Question 17

what are the 3 vitreous zones?

Answer 17

1. Cortex (most dense)
2. Intermediate Zone Cloquet’s
3. Canal

Question 18

what zone is the Outermost portion of vitreous?

Answer 18

vitreous cortex

Question 19

how thick is the vitreous cortex (hyaloid surface)?

Answer 19

100 um thick

Question 20

what is the vitreous cortex composed of?

Answer 20

Composed of densely packed collagen fibrils, cells, protein, and mucopolysaccharides

Question 21

the vitreous cortex is Divided into anterior and posterior cortex via what?

Answer 21

vitreous base

Question 22

the vitreous base extends where?

Answer 22

extends 2mm anterior to ora serrata and 3 mm posterior (2-3 um thick)

Question 23

Collagen extends at right angle to vitreous base but runs parallel to what structures?

Answer 23

to the retina and pars plana and embed firmly in the ILM of the retina

Question 24

Vitreous has its strongest attachment at:

Answer 24

the vitreous base

Question 25

the posterior cortex extends where?

Answer 25

extends posterior to the vitrous base and is in contact with the ILM of the retina

Question 26

Anterior cortex extends where?

Answer 26

extends anterior to the vitreous base and is adjacent to the ciliary body, posterior chamber, and the lens

Question 27

what acts as phagocytes? and where are they most numerous?

Answer 27

Hyalocytes synthesize hyaluronic acid, proteins

most numerous at the vitreous base

Question 28

Fibroblasts synthesize what?

Answer 28

Fibroblasts synthesize collagen fibers in the vitreous

Question 29

vitreoretinal interface:

Answer 29

The outermost portion of the posterior cortex contains anchoring fibrils that merge with the internal limiting membrane of the retina

Question 30

what does the vitreoretinal interface consist of?

Answer 30

consists of a basement membrane and the foot processes of the Muller cells of the retina

Question 31

Vitreous attachments are very firm at:

Answer 31

VITREOUS BASE – AROUND THE OPTIC NERVE (WEISS RING) – BLOOD VESSELS –AREA SURROUNDING MACULA

Question 32

Strands pass through the ILM of the retina to surround what?

Answer 32

the retinal vessels in the nerve fiber layer.

Question 33

This arrangement may cause the hemorrhages that occur due to what?

Answer 33

to vitreo-retinal traction

Question 34

the intermediate zone contains fibers that are what?

Answer 34

Contains fibers that are unbranched, run anteroposteriorly

Question 35

intermediate zones arise and insert where?

Answer 35

Fibers arise at the vitreous base that extend and insert into the posterior cortex

Question 36

cloquet’s canal:

Answer 36

1-2 mm wide channel running through the center of the vitreous body

Question 37

what structure contained the hyaloid vasculature during embryonic development?

Answer 37

cloquet’s canal

Question 38

where does Cloquet’s canal extend?

Answer 38

–Extends anteroposteriorly from the retrolental space behind the lens to a funnel-shaped area over the optic nerve head (area of Martegani)

– It is differentiated gel devoid of collagen filaments

Question 39

what are 3 components of cloquet’s canal?

Answer 39

1. Tunica Vasculosa Lentis
2. Hyaloid Vascular System
3. Glial Sheath

Question 40

Mittendorf’s Dot:

Answer 40

The remnant of the hyaloid vasculature system within the annulus of the ligamentum hyaloideacapsulare

Question 41

Bergmeister’s Papilla:

Answer 41

Remnant of glial tissue from the hyaloid vasculature

Question 42

T/F: Vitreous continues to shrink and collagen fibers aggregate forming floaters that float within the lacunae

Answer 42

T

Question 43

posterior vitreous detachment

Answer 43

weiss ring

Question 44

asteroid hyalosis

Answer 44

Degenerative process Calcium-Lipid complexes Collect in the vitreous humor