Vision and Aging (sensory) Flashcards

1
Q

Why does pupil size decrease as we age?

A

Due to greater IRIS DILATOR atrophy vs iris sphincter atrophy

NOTE: this causes an INC in Depth of Focus (refract in 0.50 to 1.00 steps bc won’t notice small steps)

NOTE: this also DEC retinal illumination (iris causes a slight decrease retinal illumination, but NOT as much as yellowing of the lens)

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2
Q

What happens when the lens increases in size as we age?

A
  1. INC in optical density from INC in axial dimension
  2. DEC retinal illuminance
  3. INC in density/size causes MYOPIC shift
  4. INC in size/stiffening contributes to onset of presbyopia
  5. Lens opacities INC light scatter & reduces contrast of retinal image
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3
Q

What aging changes occur to corneal clarity and sensitivity?

A

Clarity: INC peripheral haze as we grow that eventually moves centrally due to endothelial cell loss

Sensitivity: loss of sensitivity due to endothelial cell loss –> therefore GAT is easier

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4
Q

What happens to the index of the vitreous as we age?

A

It increases –> might be responsible for hyperopic shift?

NOTE: syneresis occurs as we age.

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5
Q

How does refractive error generally change between 40-70 years old?

A

Hyperopic shift!!!!!

Myopia DECREASES

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6
Q

How does refractive error generally change >70 years old?

A

Myopic shift (prob due to lens change)

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7
Q

What happens to astigmatism as we age?

A

It INCREASES

NOTE: corneal astigmatism stays constant with age HOWEVER, lenticular astigmatism INCREASES in ATR

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8
Q

Research shows what happens to EOM fibers with age?

A

They atrophy

Therefore, versions become slower

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9
Q

What happens to dark adaption with age?

A

Overall loss of dark adaptation sensitivity & slower rates of dark adaptation

NOTE: this is due to ROD PR LOSS & some rod outer segment enlargement. The rate is lower because rhodopsin regeneration is slower (may be related to INC thickness of Bruch’s membrane)

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10
Q

Light detection thresholds will not be as good due to what?

A

Reduced CONVERGENCE

But VA decrease due to INC convergence at the fovea

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11
Q

What happens with high contrast VA with age?

A

Does not fall off … it has a threshold that is MORE robust with age than other psychophysical properties

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12
Q

In low vision, greater than how many lines of difference btwn high and low contrast VA is a red flag for poor contrast?

A

2 lines

NOTE: after 70 contrast VA starts to get worse

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13
Q

Young people only take ~10 sec to recover from glare. How long does it take a 90 year old to do the same task?

A

1 minute

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14
Q

With cataracts removed what does the fundus appear to look like now?

A

Blue-ish hue

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15
Q

When does effective VF decrease for older pts?

A

Multi-tasking

NOTE: useful VF declines with age –> reduced speed of visual processing, reduced ability to divide attention, reduced salience of the target against its background

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16
Q

What is the most useful measurement for driving ability?

A

Useful FOV

17
Q

Which psychometric thresholds is most robust with age?

A

Critical flicker frequency (CFF)

High Contrast VA –> Low contrast VA falls off (2X worse) 10 years before high contrast VF

18
Q

Which psychometric thresholds are LEAST robust with age?

A

Attentional field area

Glare recovery time

Disability glare

19
Q

Which types of color temperatures are worse with age?

A

Higher color temperatures bc short wavelengths are not as effective

Therefore, lower color temperatures are BETTER

20
Q

What causes most of the normal aging changes in vision?

A

DEC retinal illuminance!!!!!

21
Q

High SF loss with age is due to DEC retinal illuminance. Why is middle SF loss with age?

A

Neural factors

22
Q

What’s more important than VA with age?

A

Spatial contrast sensitivity bc it correlates to face recognition (a middle SF task) & correlates to mobility