Violet light reduces light-induced retinal damage in a murine model

Abstract

Purpose : Age-related macular degeneration (AMD) remains a leading cause of blindness among the elderly in developed countries. Especially for dry AMD, although new treatments have been approved recently, there are limited treatment options and the effectiveness is still unclear.
Violet light (VL; 360-400 nm) has been reported to suppress myopia progression in animals and humans, accompanied by suppression of both ocular axial elongation and choroidal thinning (Torii et al. EBioMedicine, 2017. Jiang X et al. PNAS, 2021). In addition, VL is reported to increase choroidal blood flow, therefore, we hypothesize that VL has a protective effect on the retina. To investigate VL’s protective effect on the retina, we have conducted a study using a murine light-induced retinal damage model.

Methods : Approximately 10-week-old BALB/c mice were separated into three groups: a control group, a light-exposure-only group (LE), and a VL-with-light-exposure group (VL+LE). All three groups were reared in a standard environment with approximately 55 lux of white light for 12 hours from 8 a.m. to 8 p.m. in a light/dark cycle. The VL+LE mice were additionally exposed to 200 µW/cm² of VL from 5 p.m. to 8 p.m. On the 8th day of VL exposure, the LE mice and the VL+LE mice were exposed to white LED light at 3000 lux for 1 hour to induce retinal light damage. On the 12th day, a full-field electroretinogram (ERG) was conducted to assess retinal function.

Results : Reduction in scotopic a-wave amplitude was found between the control and LE groups as expected (0.5 cds/m²: 5-fold, p = 0.007; 2 cds/m²: 4-fold, p = 0.010; 10 cds/m²: 5-fold, p = 0.002). Compared to the LE group, VL+LE group exhibited increased a-wave amplitudes (0.5 cds/m²: 2.4-fold, p = 0.009; 2 cds/m²: 2.1-fold, p = 0.035; 10 cds/m²: 2.4-fold, p = 0.013). A similar but mostly nonsignificant trend was recognized in scotopic b-waves.

Conclusions : In this study, VL has been shown to suppress the degradation of retinal function following light-induced damage, thus offering evidence of VL’s protective effect on the retina and a possibility of new treatment for dry AMD.

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