Abstract
Purpose :
Although it is well established that correcting astigmatism with toric contact lenses improves clinical vision measures, less is known about their impact on real-world task performance using modern digital devices, such as smartphones. This prospective, repeated measures randomised crossover trial aimed to understand how toric soft contact lenses impact functional near vision performance using digital devices, in comparison to spherical equivalent contact lenses.
Methods :
Fifteen healthy young adults (mean age 23.6 ± 2.8 years) with low to moderate levels of astigmatism (-0.50 D to -1.50 D, mean -1.04 ± 0.31 D) participated. Following a screening and contact lens fitting, participants attended two separate visits where they wore either a toric or a best sphere soft contact lens correction (lens material Verofilcon A), while near visual acuity (VA) was measured. Brief (~2 minutes) reading tasks (high and low contrast) were then performed on a smartphone. Mobile eye tracking data provided objective measures of visual fatigue such as reduced palpebral aperture height and near working distance during the task.
Results :
Near VA was significantly better with the toric lens compared to the best sphere (mean difference: -0.09 ± 0.09 logMAR, p = 0.001). During the smartphone reading tasks, the average reading speed with the toric lens was 5 ± 13 words per minute faster than with the best sphere lens, however the difference was not statistically significant (p = 0.18). Significantly less reading errors were made with the toric (4.5 ± 3.3) compared to the best sphere lens (6.1 ± 4.3 errors) during the low contrast reading task (p = 0.04), but not for high contrast (p >0.05). Palpebral aperture height was 0.3 ± 1.3 mm wider and near working distance 0.31 ± 0.8 D longer, when reading with the toric contact lens. Although the main effect of lens was not significant for either measure (p >0.05), a significant lens by time interaction was found (both p < 0.05), with a closer working distance and narrower palpebral aperture observed towards the end of the reading task with the best sphere lens.
Conclusions :
Findings demonstrated significant visual and functional benefits for digital near visual tasks associated with toric contact lens correction. Improved near VA, reading accuracy, as well as an increased near working distance and palpebral aperture height during reading on a smartphone were observed.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.