Soft toric contact lens correction of moderate astigmatism improves digital reading performance and oculomotor...

Reading on digital devices is a crucial daily activity. In this study, oculomotor behaviour and reading performance were evaluated in patients with low to moderate astigmatism corrected with spherical or toric lenses, before and after a short reading task on a tablet. ΜETHODS: Silent reading performance and visual acuity (VA) of twenty four volunteers (age: 30 ± 8 yrs) was assessed binocularly with IReST passages (0.3 logMAR print size) for two contrast levels (100 % and 10 %) at 40 cm screen distance. Participants were corrected for their binocular myopic astigmatism using daily disposable contact lenses (PRECISION1, Alcon Laboratories) in either single vision (spherical) or toric design (of 0.75D or 1.25D cylinder). Recordings were repeated after a 10-minute reading activity on a tablet. Eye movements were monitored with an infrared eyetracker. Data analysis included computation of reading speed and a range of oculomotor indices.

Average VA improved at near with toric compared to spherical lens correction at both contrast levels (high: 0.06 ± 0.07 logMAR, p = 0.001; low: 0.12 ± 0.10 logMAR, p < 0.001). Conversely, statistically significant improvements with toric lenses in reading speed (faster by 27 ± 50 wpm, p = 0.023) and the number of fixations (improved by 0.07 ± 0.12 fpw, p = 0.003) were only found for the low contrast texts before tablet use, while average fixation duration was shorter (10 ± 20 ms, p = 0.028) after tablet use. When comparing the two cylindrical corrections, reading speed improvement with toric lens correction was statistically significant only with the 1.25D cylinder for both high (52 ± 58 wpm, p = 0.001) and low (57 ± 56 ms, p = 0.024) contrast texts. The reading task on the tablet had no impact on reading performance.

In contrast to VA, reading speed and oculomotor behaviour was found improved only in the correction of moderate astigmatism with soft toric lenses of 1.25D cylinder. Additionally, the 10-minute digital reading task did not influence reading performance.

The study was supported by an investigator-initiated study grant from Alcon (IIT# 73072439).