SKILL card results in amblyopic children.

Abstract

Two experiments were undertaken to assess high contrast-high luminance (HCHL) and low contrast-low luminance (LCLL) visual acuity as measured with the Smith-Kettlewell Institute Low Luminance (SKILL) card, in childhood amblyopia. In experiment 1, HCHL and LCLL visual acuity was measured in 11 amblyopic children and in 12 normal children of similar age. The results revealed that HCHL visual acuity was similar in the normal eyes and in the amblyopes' dominant eyes, and was abnormal in 91% of the amblyopic eyes. LCLL visual acuity was significantly worse in normal eyes compared to the amblyopes' dominant eyes, and was abnormal in only 64% of the amblyopic eyes. In experiment 2, HCHL and LCLL visual acuity was measured in seven previously tested amblyopic children, after a 5-month interval, and in six additional amblyopic children. In the amblyopic children who were tested twice, significant test-retest reliability for HCHL and LCLL visual acuity was found and visual acuity varied by 3.6%. The results of experiment 2 corroborated the results of experiment 1 from the amblyopic children. It is concluded that visual acuity in the amblyopic eye tends to normalize under low contrast-low luminance conditions. In addition, the mechanism(s) underlying amblyopia appear also to influence the dominant eye, resulting in superior visual acuity under low contrast-low luminance conditions.