Visual development, amblyopia and vision screening in childhood — formative SAQs

SAQ 1 — The child who sees well with both eyes open (10 marks, 15 minutes)

A five-year-old girl attends school-entry vision screening. With both eyes open she manages perfectly, but when the right eye is occluded she reads only the top line of the chart with the left (an acuity of about 6/60, or 1.0 logMAR) that does not improve with a pinhole. The eyes are structurally normal, the red reflexes are symmetric, and the cover test shows no manifest turn. ^[2]

a) Define amblyopia and explain why this is a cortical rather than an ocular problem. (2 marks) ^[2]

b) State the screening acuity refer threshold that should have triggered referral, and explain why a both-eyes-open check can miss this deficit. (2 marks) ^[1]

c) Outline the stepwise management, naming the first intervention and the two occlusion or penalisation options supported by the Pediatric Eye Disease Investigator Group trials. (4 marks) ^{[4] [5]}

d) Give the population-level justification for universal preschool screening in one sentence. (2 marks) ^[7]