Table 1. Inclusion/exclusion criteria for participants.

Inclusion Criteria

Children aged 5 to 15 years

No history of ophthalmological disease that could cause a visual field defect, but including children with refractive error, unilateral amblyopia and strabismus, where the fellow (normal) eye was to be tested. No prior experience of perimetry.

Visual acuity of 0.2 LogMAR or better (20/32 Snellen equivalent) in the tested eye

Exclusion Criteria

Children with any impairments, such as severe learning disability, which would make co-operation with formal perimetry challenging

Children not accompanied by a parent or legal guardian