Short-term effect of blue blocking lenses on axial length and choroidal thickness in young adults

Abstract

Purpose : Altering the spectral composition of light influences eye growth and refractive development in animals, and may play a role in regulating eye growth in humans. Blue-blocking (BB) spectacle lenses are marketed towards those who use digital devices regularly such as children and adolescents, and claim to reduce digital eye strain through reduced short-wavelength light transmission. This prospective, interventional study was conducted to determine whether BB lenses influence the diurnal fluctuations in axial length (AxL) and subfoveal choroidal thickness (SFChT) over a 7-day period.

Methods : Fifteen young adult emmetropes (mean age 21±2 years) (mean spherical equivalent between +1.00 and –0.25 D, astigmatism ≤ 0.50 DC) had AxL (Lenstar LS-900) and SFChT (Nidek RS-3000 OCT) measured at 4 times during the day (08:30, 11:30, 14:30, 17:30) before and after 7-days of BB lens wear. After the final measurement at baseline (day 0), participants were given spectacle frames with plano lenses with Essilor® Crizal Prevencia® BB coating to wear during all waking hours until the final measurement session on day 7. Repeated measures analysis of variance (RM-ANOVA) was conducted to examine differences in AxL and SFChT with testing day (day 0, control vs day 7, BB lens wear), time of day, and any interactions. One participant was excluded from analysis due to missing data.

Results : AxL (n=14) varied significantly across the day (p≤0.05), but there was no significant change in these diurnal AxL variations following BB lens wear (p>0.05), and no significant time-of-day by testing-day interaction (p>0.05). AxL was shortest at the 08:30 measurement, and significantly increased by (mean change ± SEM) 9±2 µm at 11:30 (p≤0.05) and 6±2 µm at 14:30 (p≤0.05), before a decrease towards baseline (08:30) levels at 17:30 (p>0.05). RM-ANOVA showed no significant diurnal change in SFChT across the day, no significant change in SFChT following BB wear, and no significant time-of-day by test-day interaction (n=14) (all p>0.05).

Conclusions : The results of this study show no evidence that 7-days of BB lens wear significantly alters diurnal AxL or SFChT changes in young adult emmetropes. However, further research in myopic children and for longer periods is necessary to exclude the influence of BB lenses on AxL and SFChT in eyes undergoing more rapid eye growth.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.