Chinese Reading Performance with Toric Versus Spherical Equivalent Soft Contact Lenses: A Participant-Masked Randomised Crossover Eye-Tracking Study

Abstract

To evaluate the impact of toric versus spherical equivalent contact lenses on visual acuity and eye-movement-based reading performance in young adults with low-to-moderate astigmatism, using Chinese reading passages to reflect real-world tasks. A participant-masked, randomised, two-period crossover study was conducted in 28 young adults (aged 18–35 years) with low-to-moderate refractive astigmatism (−0.75 to −2.00 dioptre cylinder [DC]). Participants wore toric and spherical equivalent daily disposable soft contact lenses (SCLs) for 1 week each, in random order. Binocular distance, intermediate and near visual acuity were measured and reading performance was assessed during silent reading of standardised Chinese passages using the EyeLink 1000 Plus. Key metrics included reading speed, fixation count, fixation per minute (fpm), fixation per word (fpw), saccade characteristics and regressions. Toric lenses significantly improved binocular intermediate visual acuity at 66 cm (−0.11 ± 0.07 vs. −0.07 ± 0.08 logMAR, p = 0.04) and reading speed (345.37 ± 122.41 vs. 322.49 ± 130.65 characters per minute [cpm], p = 0.03), compared with spherical equivalent lenses. Additionally, toric correction was associated with more efficient eye-movement behaviour, including fewer fixations per word, fewer total fixations, fewer total saccades and fewer regressions (all p < 0.05). Toric SCLs improved intermediate visual acuity and Chinese reading performance relative to spherical equivalent correction in young adults with low-to-moderate astigmatism. These findings support the functional benefit of full astigmatic correction for visually demanding mid-range reading tasks.