Contrast Sensitivity and Low-Contrast Visual Acuity in Children With Low Vision

To investigate distance and near contrast sensitivity (CS), as well as low-contrast visual acuities (LCVAs) at 5% and 2.5% contrasts across various eye diseases causing low vision, in children aged 5 to <16 years, and to study the repeatability of these measures.

In total, 782 children (age, mean ± SD, 10.23 ± 2.75 years) with low vision, visual acuity between 0.3 and 1.3 logMAR, or visual field with mean deviation worse than 12 dB were recruited. CS was assessed with Pelli-Robson distance and near tests. Visual acuity and LCVAs at 5% and 2.5% contrast were assessed using LEA symbols. In 134 children, data were collected again in approximately 3 months for repeatability measures. Bland-Altman 95% limits of agreement (LoAs) were used to assess repeatability.

A wide range of CS (distance: 1.69 to 0.45 logCS, near 1.73 to 0.15 logCS) and LCVA (0.80 to 1.54 logMAR at 5% contrast and 0.94 to 1.58 logMAR at 2.5% contrast) were observed across 47 eye diseases in children with low vision. Repeated measures for CS and LCVA exhibited a large variation (LoA: distance CS = 0.44 logCS, near CS = 0.54 logCS, LCVA 5% = 0.38 logMAR, LCVA 2.5% = 0.42 logMAR) in children with low vision.

CS and LCVA impairments vary across eye diseases in children. A difference of more than 0.45 logCS (three triplets) in CS or 0.4 logMAR (four lines) in LCVA during follow-up is considered clinically meaningful for children with low vision due to high test-retest variability.