3. Visual milestones
• Birth Bright lights
• 7 days vestibulo-ocular reflex
• 3 mos transient fixation & following
• 6 mos fixation & following
even for distance
• 2-3 y 20/30
• 5-7 y 20/2
14. School age child
• Not infants and toddlers
• Preschool 3-6 years
• Regular School 7-12
• Adolescent 13-18
15. Vision testing
• Quantifiable
• Depends on patient discrimination
• Depends on examiner ability to interpret
response
• Standard: Snellen acuity: optotype
• Psychophysical tests: test interpretation
subjective measured by patient’s ability to
communicate recognition to examiner
16. Preschool
• Short attention span
• Inability to sustain interest
• Language and communication barriers
• Cultural and social limitations
17. Preschool Tests
• Detection acuity tests
– Stycar graded balls (Sheridan 1973)
– Catford drum (Catford & Oliver 1973)
– Dot visual acuity test
• Recognition acuity test
– Direction oriented: Illiterate E, Landolt C
– Picture charts
– Letter charts
18. Vision Assessment: 3-6 years
• Allen pictures: cultural bias
• Sheridan Gardner or HOTV/HOTEX
• Illiterate E / tumbling E / E game
• Landolt C
• Snellen numbers, letters
– kids memorize!
• Sloan Letters
19. Visual Acuity Testing
• Test Charts
– HOTV / HOTEX
– Tumbling “E” Game
– Landolt C
– Picture Charts
23. Grating vs Snellen Acuity
• Grating acuity (cycles
per degree)
• Snellen acuity (visual
angle)
• Grating overestimates
Snellen
24. Limitations of Optotype Test
• Snellen acuity unreliable before age 6-8
• Not all children will know alphabet &
numbers
• Single optotypes may overestimate linear
acuity
27. Susceptible Period
• Most sensitive first 2-3
years
• Decreases until age
6-7 years (12? 18?)
– complete visual
maturation
– retinocortical pathways
and visual centers
resistant to abnormal
visual input
28. 7-12 years
• Significant number still will not express
poor vision
• Easy to perform Sloan linear acuity testing
33. Vision Assessment: Nystagmus
• Binocular near vision test
– allow patient to assume own distance
– test at standard near distance
– check head posture
– VA in forced primary
• Binocular distance vision
• Monocular distance & near vision
34. Vision Assessment: Nystagmus
• Monocular occlusion
– many will increase nystagmus
• Remote occlusion
• Sufficient fogging: know refraction!
• Neutral density filters
• AO vectograph testing
• Translucent occluder
35. Random dot stereograms
• 2 plates of randomly
displayed dots, one
plate to each eye
• Shape of figure
displaced horizontally
relative to other plate
• No monocular cues
• Normal may fail