TOPIC 4: VA

Question 1

what is VA at birth? what VA is considered norm at age 3? when do they get 6/6 VA?

Answer 1

6/300
6 / 9 is “normal” at age 3.

Children do not normally have 6 / 6 vision until some time after age 3
visual acuity of an infant will continue to develop rapidly and approach adult level by about 3 to 5 years old.

Question 2

what kind of VA is present from birth-3 yo and above 3yo?

Answer 2

birth-3 yo: near VA only
above 3yo: near and distance VA

Question 3

what are the recommended 7 VA tests for 18 to 36 months old child (Toddler)?

Answer 3

1. Cardiff acuity card
2. LEA symbol cards
3. Kay Pictures
4. Broken Wheel test
5. Sheridan Gardiner
6. Keeler LogMAR
7. Computer optotypes

Question 4

what are the recommended 2 VA tests for ≥ 36 months old child (Child)?

Answer 4

1. Standard Snellen chart
2. LogMar Charts

Using:
Optotypes - Tumbling E/Landolt C etc.
Computer optotypes - Crowded optotype/Confusion Bar

Question 5

what are the 6 recommended VA tests for infant to 18 months old? (infant)

Answer 5

1. Differential Occlusion Objection (DOO)
2. Preferential looking (PL)
3. Fixate and Follow
4. OptoKinetic Nystagmus (OKN)
5. STYCAR Test
6. Visually Evoked Potential (VEP)

Question 6

what are the recommended Visual Acuity Test for >36 months old child (child)?

Answer 6

Standard Snellen chart

LogMar Charts Using:
Optotypes - Tumbling E/Landolt C etc.
Computer optotypes - Crowded optotype/Confusion Bar

Question 7

what is the use of DOO?

Answer 7

For babies and young children, we need to check their response to one eye being occluded.

Question 8

results for DOO?

Answer 8

Children with symmetrical vision should respond equally, or not at all to sequential occlusion of the eyes.

Children with unequal vision typically become fussy or agitated when the BETTER eye is covered as seen in Picture B.

Repeat test for confirmation.

Question 9

3 tests for preferential looking? principal for PL?

Answer 9

1.Teller acuity cards
2. Keeler acuity cards
3. LEA grating paddles

Principle: Grating appears grey when it cannot be resolved

Question 10

expected results for PL?

Answer 10

2 targets are presented: one with detail and one without
Infant will look at the one with detail.

Question 11

Fixate and Follow target? what is it used to evaluate?

Answer 11

Target: Transilluminator / Face / Toy

evaluation of:
Response to light
Note: Lid closure to bright light ≠ cortical function
Tracking ability
Comparison of ability of each eye

Question 12

what does a delay in follow and fixate indiate?

Answer 12

Possible prematurity
Possible generalized motor delay
Possible Visual System Diagnosis

Question 13

procedure for fixate and follow?

Answer 13

-Cover one eye
Examiner hand/thumb, Parent’s hand

-Light directed at patient’s face

-Obtain fixation with non-occluded eye
May tap/flash/move light

Question 14

recording for fixate and follow?

Answer 14

F&F = able to fixate and follow target

CSM:
Central – light reflex = central
Steady – eye maintains alignment with stationary and moving object
Maintenance – under binocular conditions does previously fixating eye maintain fixation

Question 15

what is OptoKinetic Nystagmus (OKN)

Answer 15

Reflex that keeps retinal image stationary when visual field is moving. Optokinetic nystagmus can be induced with an optokinetic drum.

OKN reflex is present at birth

Question 16

tests to induce OKN? disadvantages?

Answer 16

Test(s):
OKN drum - Adult or Paediatric version
Catford drum
Largely overtaken by PL nowadays

Disadvantage:
Motion-detecting device only
Cases of positive response even with no central vision / greatly impaired vision

Question 17

what is the 100s and 1000s (Hundreds and Thousands) test?
VA if can pass test?

Answer 17

A younger child’s vision can be assessed with toys, small object like raisins or a “hundred & thousand” sweet test.

If the child is able to pick up a small sweet at 33cm, visual acuity is at least 6/24 or 20/80.

Question 18

STYCAR Test, 3 procedures of graded ball test?

Answer 18

STYCAR stands for Sheridan Test for Young Children and R slurs.

3 Procedures of Graded Ball test:
The Rolling Ball Test
The Mounted Ball Test
The Peripheral Field Test

Question 19

what is Visually Evoked Potential (VEP)?

Answer 19

“Evoked” responses arise from external stimulus and disappear when the stimulus is removed

VEP is a summed cortical response resulting from a change in the stimulus (e.g. luminance, size)

Generated in visual cortex
Sensitive to refractive error
Specialist technique

Question 20

disadvantage of VEP?

Answer 20

Disadvantage:
Invasive technique
Test input of visual system only

Question 21

8 Clinical presentations of Reduced VA in infants and toddlers?

Answer 21

Rubbing eyes
Poor tracking
Failure to recognize familiar faces
Inattentiveness
Excessive clumsiness
Poor eye contact
Lack of interest on small objects
No signs or symptoms

Question 22

6 Clinical presentations of Reduced VA in preschool-School age

Answer 22

Avoidance of near work
Poor fine motor coordination/poor athletic
Shyness
Squinting or brow ache
Headaches
Holding book close
No signs or symptoms

Question 23

what is method of occlusion by age

Answer 23

> 3 years old:
From an infant till toddler: an adhesive (stick-on) patch is advised to prevent peeking through.
*When amblyopia suspected, it is recommended to use black elastic or adhesive patch to prevent peeking.

Young child between 3 to 7 years old:
Black patch with elastic (pirate patch)
Paediatric trial frame
*Recommended as it looks fun and interesting to the child.
*When amblyopia suspected, it is recommended to use black elastic or adhesive patch to prevent peeking.

Older child of 7 to 10 years old:
Simple black patch with elastic
Trial frame and occluder
*When amblyopia suspected, it is recommended to use black elastic or adhesive patch to prevent peeking.

Above 10 years old:
Handheld occluder
Trial frame and occluder