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Ocular Physiology > 9 Aging And The Cornea > Flashcards

9 Aging And The Cornea Flashcards

1
Q

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

A

True

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2
Q

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

A

2/3

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3
Q

When does the cornea reach adult size

A

Age 3

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4
Q

The sclera grows to what age

A

10-12

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5
Q

When do most eyes become emmetropic

A

6-8

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6
Q

Aging changes to the cornea impede vision

A

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

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7
Q

As we age what happens to corneal sensitivity

A

It decreases

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8
Q

As we age what happens to light scatter

A

It increases

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9
Q

Does teh cornea get flatter or steeper as we age

A

Flatter

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10
Q

What happens to Bowmans membrane

A

It stipples

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11
Q

What happens to descemets membrane

A

Thickens

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12
Q

What is the most common aging change in the cornea

A

Arcus

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13
Q

What is arcus

A

An annular yellow-white deposit in the peripheral stroma

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14
Q

What makes the deposits in arcus

A

Cholesterol and cholesterol esters

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15
Q

What can cause arcus

A

Age or elevated blood cholesterol levels

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16
Q

Should we be concerned when we see arcus

A

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

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17
Q

by age 50 what percent of the population has arcus

A

50%

18
Q

By age 80 what percent of the population has arcus

A

100%

19
Q

Is arcus unilateral or bilateral?

A

Bilateral

20
Q

What changes happen in the corneal epithelium

A

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

21
Q

What does loss of intracellular junctions in the corneal epithelium cause

A

Breakdown of the epithelium function

22
Q

Decreased keratocyteis in the epithelium affects what

A

Wound healing

23
Q

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

A

Opacities

24
Q

What is the Hudson-Stahli line?

A

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

25
Q

What is the Kimble girdle of Vogt

A

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

26
Q

What are Hassall-Henle bodies?

A

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

27
Q

What happens to endothelial cell density

A

Decreases with cell loss

28
Q

What changes occur in endothelium

A

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

29
Q

What are Krukenbergs spindle

A

Pigment deposits in posterior cornea with vertical orientation

30
Q

What happens to corenal sensitivity with age?

A

Decreases due to loss of corenal nerves

31
Q

What must occur for emmetropizaton happen

A

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

32
Q

What is the usual cause of refractive error

A

Eye length

33
Q

When does myopia occur

A

8-14 years

34
Q

What is the main cause of myopia

A

Lengthening of posterior eye

35
Q

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

A

Increased

36
Q

What does scleral remodeling cause

A

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

37
Q

What is scleral ectasia

A

Tissue bulge on the sclera caused by thinning

38
Q

What refractive error has a higher risk of ectasia?

A

Myopia

39
Q

As fatty deposits accumulate what happens to the sclera

A

Yellows

40
Q

What happens to proteoglycans in the sclera

A

Decrease

41
Q

What happens to the lamina cribrosa

A

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

Ocular Physiology (8 decks)

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