Functional vision and symptoms associated with prolonged digital device use in astigmatic contact lens wearers

Prolonged digital device use can result in digital eye strain which may be exacerbated by uncorrected astigmatism. This study explored how sustained smartphone reading impacts on visual function and symptoms when astigmatism is corrected with disposable soft toric contact lenses.

30 adult contact lens wearers (mean age 23 ± 4 years, mean astigmatism 1.12 ± 0.35 D) habitually using digital devices for ≥10 h/day were fitted with Delefilcon A daily disposable toric contact lenses for 14-days. High and low contrast near visual acuity (VA) were assessed before and after a prolonged smartphone reading task on day 1 and day 14 of lens wear. The severity of digital eye strain symptoms were reported using a 0-100 visual analogue scale following the reading task. Contact lens dry eye symptoms were assessed using the 8-item Contact Lens Dry Eye Questionnaire (CLDEQ-8).

At baseline, the mean high and low contrast near VAs were - 0.08 ± 0.05 and + 0.04 ± 0.08 logMAR, respectively, which did not decline significantly following the prolonged reading task, or after 14 days of lens wear. The average reading speed was not significantly different between day 1 and day 14 of lens wear (251 ± 85 words-per-minute vs 252 ± 80 words-per-minute, p = 0.47). Digital eyestrain symptoms following the reading task (mean of all symptom scores: 13 ± 21) remained stable over the 14-days of lens wear (all p > 0.05), and > 75% of the reported symptoms were ranked as <15/100 in severity. The mean CLDEQ-8 score was 15.2 ± 8.8.

The correction of astigmatism with disposable toric contact lenses provided stable functional visual performance, with minimal digital eye strain during a prolonged smartphone reading task. However, over half of participants, reported significant dryness/discomfort (CLDEQ-8, ≥12) during 2-weeks of wear, highlighting a disconnect between short-term digital task symptoms and overall daily lens comfort in participants habitually using digital devices for ≥10 h/day.