Retina and Vitreous Vol. 1 Flashcards Preview

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Flashcards in Retina and Vitreous Vol. 1 Deck (32):
1

What percentage of the volume of the globe does the vitreous occupy?

80%

2

Name the 3 components of the vitreous.

1. Water 2.Collagen 3.Hyaluronic acid

3

What is the name of the retrolental indention of the anterior hyaloid membrane of the vitreous?

Patellar fossa

4

Where is the vitreous base located?

Straddles the ora serrata, from 2 mm anterior to 3 mm posterior

5

Name the 4 locations of firm vitreous attachment.

1. Vitreous base 2.Retina vessels 3. Optic disc 4. Macula

6

When does liquefaction of the vitreous start?

As early as age 2

7

What pocket does liquefaction of the vitreous form early in life?

Premacular bursa, or precortical pocket

8

During vitrectomy, what medication can be introduced to highlight vitreous liquefaction cavities?

Triamcinolone

9

What causes the yellow color of the macula?

Carotenoids (e.g. lutein and zeaxanthin)

10

What are the two functions of the carotenoids?

1. Antioxidants 2. Filter blue light

11

Where is the fovea located in relation to the optic disc?

4 mm temporally and 0.8 mm inferior

12

Where are the dentate processes located?

Peripheral retina

13

Where are dentate processes most prominent?

Nasal peripheral retina

14

What can an enclosed ora bay be confused for?

Peripheral retinal hole

15

What are the dentate processes?

Small portions of retina projecting into the ora serrata

16

What are ora bays?

Extensions of the pars plana extending onto the retinal side

17

How many degrees of the visual field does the fovea constitute?

Approx. 5 degrees

18

What causes an enclosed ora bay?

Connections between dentate processes and ora bays

19

What are the only types of cells found within the central fovea?

Cones and Muller cells

20

What is the anatomic boundary of the foveola?

Area within the fovea that lacks the ganglion cell layer and inner nuclear layer

21

Where are cones most heavily concentrated?

Central fovea

22

Where is concentration of rods the greatest?

Approx. 20 degrees from fixation

23

What is the density of rods approx. 20 degrees from fixation?

160,000 rods/mm2

24

What are the two components of rhodopsin?

Vitamin A and opsin

25

What photoreceptor contains rhodopsin?

Rods

26

Where is opsin located within the cones?

Photoreceptor outer segments

27

How many types of opsin are found within cones?

Three (red, green, and blue)

28

What phagocytizes the discs of rods once they are shed from the outer retina?

RPE

29

What gene encodes for ABCR protein?

ABCA4

30

What material accumulates in the retina and RPE in Stargardt disease?

Retinoid-based fluorophores (e.g. A2E)

31

What protein is defective in Stargardt disease?

ABCR

32

What accumulates in the outer segments of photoreceptors in Stargardt disease?

All-trans-retinol