Normal Visual Dev in Children & Adolescents

Question 1

What are the different types of acuity

Answer 1

1. Resolution acuity (grating acuity)
2. Recognition acuity (various vision charts)
3. Vernier acuity (hyperacuity); can you differentiate slight offset.

Question 2

What are 3 ways to assess resolution acuity

Answer 2

1. Visual evoked potential (VEP)- objective
2. Optokinetic Nystagmus (OKN)-objective
3. Preferential Looking (PL)-behavioral method

Question 3

Describe how you measure acuity by OKN

Answer 3

When we have a visual env with a certain feature rotating around us, you get reflex moment until eyes can’t normally track. You got slow tracking and fast tracking. Its a reflex response that you cannot control. The idea is that when you show rotating black/white stripe, if they can see pattern, and high spatial frequency reaches a point where subject can’t see it, will show a gray pattern. Babies can be tested this way right after birth

Question 4

T/F Is OKN indicative of subject seeing 100%

Answer 4

F; OKN response is more controlled by region that is controlling oculomotor response instead of going directly to primary visual cortex. Showing a positive OKN response does not mean that subject sees 100%.

Question 5

Describe VEP method

Answer 5

Need 3 electrodes hooked to skull. If visual stimuli presented, it should stimulate an electric response, if there is a positive response, electrode records response, indicating the pattern is being percieved

Question 6

What is most commonly used pattern

Answer 6

Pattern reversal: checkerbox pattern. Strong visual stimuli. You can vary size checker box from small to large spatial frequency pattern.

Question 7

When using VEP method, VA starts at _____ in infants and increases to _____ by 6-8 months

Answer 7

20/600; 20/20

Question 8

T/F VEP and OKN agree with each other

Answer 8

True

Question 9

How does FPL work

Answer 9

Present 2 choices; 1 with gray uniform pattern and one with black and white stripe. If they can see pattern they prefer to look at pattern. If baby can resolve pattern they look towards babies left side and examiner notices this. If you makes stripes thinner, the two choices will look similar and won’t show preference for either which determines threshold for VA

Question 10

At 1 month, a FPL VA of 1 cycle/degree is Snellen equivalent of _____

Answer 10

20/600

Question 11

At 3 months, a FPL VA of 3 cycles/degree is Snellen eq of

Answer 11

20/200

Question 12

At 6 months, a FPL VA of 6 cycles/degree is Snellen eq of ______

Answer 12

20/100

Question 13

At 12 months, a FPL VA of 12 cycles/degree is Snellen eq of

Answer 13

20/50

Question 14

Between 3-5 years 30 cycles/degree is Snellen equivalent of _____

Answer 14

20/20

Question 15

With the Teller acuity card, you present from 50 cm to 1 m away, if they show preference towards correct direction, then you go to higher spatial frequency card, however there are disadvantages:

Answer 15

1. very expensive

2. each card is 1 m long; not mobile

Question 16

What are Lea Grating paddles

Answer 16

Much smaller than teller acuity cards, more mobile, they have patterns like the the teller acuity card.

Question 17

Describe the Cardiff Acuity Test

Answer 17

You have small card. one side is grey the other is made by black and white pattern which becomes thinner and thinner.. Much cheaper to carry around but not as good as teller acuity card.

Question 18

Pattern dev of ____ is much faster at reaching adult level at 6-8 months. _____ reaches adult level at 3-5 years old.

Answer 18

VEP; FPL

Question 19

T/F The behavioral method of testing VA has much higher cortical demand.

Answer 19

T; this is why you have lower value for PL. Doesn’t mean one is more accurate than the other method

Question 20

What are limiting factors for VA development in infants

Answer 20

1. Foveal cone immaturity; most impt
2. Incomplete myelination of the optic pathway.
3. Cortical immaturity

Question 21

A ____ OS is inefficient at detecting light. A ____ IS means cones aren’t tightly packed. You get a 4-8 fold increase in cone density in the final stage of central retinal dev from 16 week post natal to adult

Answer 21

short; fat

Question 22

what are issues that can limit resolution acuity development

Answer 22

1. Development and distribution of cortical neurons

2. Developing connectivity in cortex and elsewhere.

Question 23

By ____ months of age, the ocular dominance columns are adult like

Answer 23

3

Question 24

The density of synaptic connection increases after birth. Low at 28 weeks after birth, and then you see a dramatic increase and reach adult like by 6 months to a year. Afterwards those ______ in synaptic connections stabilize throughout adult life, whereas _____ decreases after you reach 20 yrs old.

Answer 24

volumes; density

Question 25

Foveal cone reaches adult length at ____ years of age. Foveal cone density reach adult level at ____ months

Answer 25

4; 45

Question 26

Complete myelination takes more than ____ years

Answer 26

2

Question 27

What are ex of recognition acuity for older children

Answer 27

1. broken wheel test
2. tumbling E
3. Lea symbol chart
4. Landolt C chart
5. Allen picture cards

Question 28

______ acuity is a measure of the eyes ability to perceive that a misalignment exists between the elements of the stimulus and is based largely on _____ processing.

Answer 28

Hyperacuity; cortical

Question 29

In an adult, ____ acuity is about 10 times better than resolution/grating acuity

Answer 29

10

Question 30

Vernier acuity actually starts out to be worse than grating acuity in new born, but then develops rapidly in the ____ year and surpass grating acuity from _____ months of age onward. Vernier acuity reaches adult level at ____ to ____ years

Answer 30

first; 4; 6; 8

Question 31

Emmetropization centers on a refractive range around low _____ to emmetropia. It ranges from ___ to +1.00

Answer 31

hyperopia; +0.50

Question 32

Most infants are _____ and average _____D. About 25% are myopic, 50% astigmatism, and 25% have anisometropia

Answer 32

hyperopic; +2.00

Question 33

Right after birth there is a wide distribution of refractive error, then it centers around ______D. There is a narrower distribution around 6 year old.

Answer 33

+2.00

Question 34

We have highest amount of astigmatism at ____ months of age and lowest amount at 6 years old, which is usually when emmetropization is reached.

Answer 34

6

Question 35

If a 5-6 year child has > or = 1.50 D of hyperopia they will remain hyperopic. If hyperopia is between ____ to _____ they will become emmetropic (-0.50 to +1.00). If hyperopia is less than ____D then they will be ______.

Answer 35

+50 to +1.25; myopic

Question 36

Asians have the highest prevalence of myopia. _____ and whites have lowest prevalence for myopia. Asians and Hispanics have the highest prevalence for astigmatism

Answer 36

african americans

Question 37

What are risk factors for myopia

Answer 37

1. Age
2. family hx
3. amount of near work
4. gender (female > male)
5. race

Question 38

Hyperopia actually tends to ____ in school aged children, between 6-12.

Answer 38

decrease

Question 39

20/20 vision in adult, its corresponding spatial frequency is_____ cycles per degree

Answer 39

30

Question 40

At _____ weeks, the VEP study shows similar to adult level at low spatial frequency which corresponds to 1 cycle per degree which corresponds to a snellen acuity of _____

Answer 40

10; 20/600

Question 41

At ____ months high frequency cut off reaches about half of the adult level if you use the VEP method to test.

Answer 41

8

Question 42

Contrast sensitivity reaches adult like by ___ to ___years of age

Answer 42

7;9

Question 43

Ocular motor function reaches adult level by:

Answer 43

3 to 6 months

Question 44

Accommodation reaches adult level by

Answer 44

3 to 4 months

Question 45

Convergence and fusion reaches adult level by

Answer 45

22 weeks (5 months)

Question 46

Stereopsis reaches adult level

Answer 46

6 months