Measuring contrast sensitivity in school children and young adults: a comparison between Pelli-Robson and SpotChecks charts.

CLINICAL RELEVANCE: Contrast sensitivity (CS) is an important component of functional vision assessment, providing information that complements visual acuity measurements. Reliable CS tests are valuable in clinical settings serving children and populations with limited access to ophthalmic equipment.

BACKGROUND

SpotChecks, a self-administered CS test, has shown good agreement with the Pelli-Robson chart (PR) chart in older adults. This study evaluated its performance in children from a Black African population.

METHODS

In this cross-sectional study, 152 children aged 5-17 years and 27 adults aged 18-37 years with normal vision were recruited. Monocular and binocular CS were measured using SpotChecks at 40 cm and PR at 40 cm and 1 m under room illumination (80-120 cd/m2). Adults were grouped into 18-25 years (n = 17) and 26-37 years (n = 10). Agreement between tests was assessed using paired t-tests and Bland-Altman analysis.

RESULTS

CS improved significantly from ages 5-8 years to older age groups (p < 0.001). Participants aged ≥ 9 years and adults showed comparable CS between SpotChecks and PR at 40 cm (all p > 0.05). However, PR at 1 m yielded lower CS scores in children than adults (monocular: 1.51 ± 0.16 vs 1.61 ± 0.15; binocular: 1.58 ± 0.13 vs 1.73 ± 0.18; p < 0.05). Agreement between SpotChecks and PR at 40 cm was good (mean difference: +0.023 logCS binocular; 95% limits of agreement: -0.28 to +0.33). PR at 1 m consistently produced lower scores than at 40 cm.

CONCLUSIONS

CS improves with age, stabilising around 9-10 years, with children aged 5-8 years showing lower scores than older groups. SpotChecks at 40 cm showed good agreement with PR at the same distance and may serve as an alternative. PR at 1 m may underestimate CS in children. Further studies should evaluate both tools in paediatric populations with visual impairment.