9 Aging And The Cornea Flashcards Preview

Ocular Physiology > 9 Aging And The Cornea > Flashcards

Flashcards in 9 Aging And The Cornea Deck (41):
1

T/F at birth the cornea has the full adult thickness

True

2

In newborns the axial length of the eye is ____ of an adults

2/3

3

When does the cornea reach adult size

Age 3

4

The sclera grows to what age

10-12

5

When do most eyes become emmetropic

6-8

6

Aging changes to the cornea impede vision

No, only if the central cornea is affected or the transparency is affected

7

As we age what happens to corneal sensitivity

It decreases

8

As we age what happens to light scatter

It increases

9

Does teh cornea get flatter or steeper as we age

Flatter

10

What happens to Bowmans membrane

It stipples

11

What happens to descemets membrane

Thickens

12

What is the most common aging change in the cornea

Arcus

13

What is arcus

An annular yellow-white deposit in the peripheral stroma

14

What makes the deposits in arcus

Cholesterol and cholesterol esters

15

What can cause arcus

Age or elevated blood cholesterol levels

16

Should we be concerned when we see arcus

NO, not unless it is in a person less than 40 y.o.

17

by age 50 what percent of the population has arcus

50%

18

By age 80 what percent of the population has arcus

100%

19

Is arcus unilateral or bilateral?

Bilateral

20

What changes happen in the corneal epithelium

Alterations in the transmembrane receptors resulting in a reduction in the adhesion molecules

21

What does loss of intracellular junctions in the corneal epithelium cause

Breakdown of the epithelium function

22

Decreased keratocyteis in the epithelium affects what

Wound healing

23

Collagen fibril degradation in the epithelium has what affect on the cornea

Opacities

24

What is the Hudson-Stahli line?

Iron deposits in the epithelium, created a horizontal pigmented line. Evident at the lower lid margin

25

What is the Kimble girdle of Vogt

Degeneration of Bowmans layer. Located at 3 and 9 o clock. Evident as a yellowish opacity

26

What are Hassall-Henle bodies?

Small round endothelial indentations caused by thickening of descemets membrane. Appear as corneal guttata

27

What happens to endothelial cell density

Decreases with cell loss

28

What changes occur in endothelium

Decrease in cell density
Polymegalism (large cells)
Pleomorphism (increased variable size and shape)

29

What are Krukenbergs spindle

Pigment deposits in posterior cornea with vertical orientation

30

What happens to corenal sensitivity with age?

Decreases due to loss of corenal nerves

31

What must occur for emmetropizaton happen

Changes in refractive components and the eye size must be well balanced during growth to allow emmetropization

32

What is the usual cause of refractive error

Eye length

33

When does myopia occur

8-14 years

34

What is the main cause of myopia

Lengthening of posterior eye

35

There is a reduced risk of myopia with (increased/decreased) outdoor activity?

Increased

36

What does scleral remodeling cause

Axial lengthening that occurs in myopia, the scleral tissue is weakened and thins

37

What is scleral ectasia

Tissue bulge on the sclera caused by thinning

38

What refractive error has a higher risk of ectasia?

Myopia

39

As fatty deposits accumulate what happens to the sclera

Yellows

40

What happens to proteoglycans in the sclera

Decrease

41

What happens to the lamina cribrosa

Becomes stiffer and less resilient making eye more susceptible to glaucomatous damage