The relationship between violet light transmittance of contact lenses and axial length elongation

Abstract

Purpose : Myopia is epidemic worldwide. We previously reported that violet light (360-400 nm wavelength), which is abundant in the outdoor environment, had a suppressive effect not only against school-aged myopia (Torii H et al. EBioMedicine. 2017), but also against adult high myopia which could be sight-threatening (Torii H et al. Sci Rep. 2017). We hypothesized that the more violet light transmittance of the contact lenses, the less axial length elongation would occur. In this study, we performed a retrospective, observational clinical study to examine the relationship between violet light transmittance of contact lenses and axial length elongation.

Methods : This study included 422 eyes of 214 children (age range, 11-20 years; average age, 14.5 ± 1.7 years) who were all contact lens users to correct myopia and followed for more than 6 months. Axial length was measured using IOLMaster (Carl Zeiss Meditec). Age, gender, and baseline axial length were adjusted using linear mixed-effect model to evaluate the association between the violet light transmittance of contact lens and the axial length elongation. A P value less than 0.05 was considered statistically significant. This clinical study was approved by the Institutional Review Board of Keio University School of Medicine.

Results : There were 16 contact lenses in which the violet light transmittance ranged from 17.96% to 99.36%. The mean baseline axial length (mm) was 25.43±1.04 (standard deviation). The mean change of axial length (mm) for 6 months was 0.09±0.07. The liner mixed effects model showed that violet light transmittance was associated with the axial length elongation (P = 0.041) and age was also associated with the axial length elongation (P < 0.001). This result suggested that less axial length elongation was associated significantly with more violet light transmittance of the contact lenses and older age.

Conclusions : Our data showed that the more violet light transmittance of the contact lenses, the less axial length elongation occurred. If further confirmed by prospective clinical trials in the future, this finding would offer a novel suppressive approach for myopia control.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.