02

Question 1

VEP (show cortical activity) shows latency DEcreasing and amplitude INcreasing until about ____ days. What happens to the amplitude after these many days? Why?

Answer 1

100 days (~6 mos): amp gets SMALLER because activity gets more COMPLEX

-VEP amps are variable, NOT a good measure of development

Question 2

T/F: Changes in VEP are dependent on cortical changes (since it’s a cortical measurement)

Answer 2

FALSE - based on DEVELOPMENT OF THE RETINA - cortex is already in place, awaiting mature ganglion cell response

Question 3

At what age is visual acuity in kittens mature?

Answer 3

3-4 months

Question 4

According to CSF…..
About what is the acuity in a 2.5 month old human?

-How about 6 months?

Answer 4

2.5 months: ~20/100 …bad

6 months: 20/40, slow improvement until 6-7 Y/O (parallel foveal development)

Question 5

What’s the most commonly used technique to check vision in infants? Which two diff. tests exist? Which test lead to teller acuity cards?

Answer 5

Preferential Looking (PL)

1) MIT two choice technique
2) U-Washington technique - teller cards

Question 6

MIT technique for PL:

• dark/lit room?
• distance?
• stripe pattern?
• percentage drops below 50% @ how many cyc/degree (what’s the vision?)
• Result: grating acuity is based on what factor?

Answer 6

• dark room, 0.5m, vertical stripes (look @ them until random performance indicates complex pattern)
• 8 cyc/deg (20/100) - VA considered to be 20/80
• MATURITY

Question 7

T/F: MIT Technique found that grating acuity is based on age, not experience or maturity

Answer 7

FALSE - it’s based as a function of MATURITY (correct graph for prematurity and it’s logarithmic)

Question 8

T/F: MIT Technique showed that CSF is highly reduced for ALL spatial frequencies in all infants

Answer 8

True

Question 9

U-Wash- Teller procedure:

• dark/lit room?
• distance?
• main results?
• rapid improvement in acuity occurs around how many months?

Answer 9

lit room, 0.5m, vert stripes looked at until random performance (can’t see)

• results: same as MIT technique (VA improves, then gradual, CSF sucks)
• 6-7 MONTHS (then slowly increases)

Question 10

Which test shows LOWER VA, and MORE reduced CSF: PL or VEP? Reflects infant’s ability to do what?
-At what age do the results approach each other?

Answer 10

PL: preferential looking

• shows ability to EFFECTIVELY USE INFORMATION in responding to environment
• b/w 1-2yrs

Question 11

T/F: Grating acuity is relatively insensitive to strabismic amblyopia and ref. error

Answer 11

TRUE - it’s quite insensitive - many show no difference

Question 12

Which is more accurate for amblyopes: teller cards or landolt C? Why?

Answer 12

Landolt C - by a landslide
-extra dimension of POSITION SENSE is required. Difference in processing a grating stimulus vs. an actual letter. Landolt C will p/u more ambloyopes.

Question 13

By how many years of age does light sensitivity in a child approach that of an adult?

Answer 13

2 years

• @ 4 wks: 25X less sensitive
• @ 18 wks: 4X less sensitive

Question 14

Which sensitivity function will be HIGHER in a child than in an adult?

Answer 14

photopic luminance sensitivity fxn: d/t higher optical CLARITY in infant

Question 15

Regarding color vision in infants, colors are more desaturated w/ (lower/higher) wavelengths

Answer 15

LOWER

-color detection is about the same in infants/adults w/ higher wavelengths.

Question 16

Infants are able to respond to a change in movement DIRECTION around __ weeks of age

Answer 16

8 weeks (takes longer if there are more revolutions/second)

Question 17

ORIENTATION of grating discrimination is possible around __ weeks, and pretty good (30 degrees) by about __ weeks

Answer 17

4 weeks; 10 weeks

Question 18

Ability to differentiate b/w different CONTOURS only happens around __ months of age

Answer 18

6 months - improves from there