Abstract
Purpose :
To investigate the influence of overexposure to light emitting diode (LED)-derived light with various wavelengths on mouse ocular surface.
Methods :
LEDs with various wavelengths were used to irradiate 6- to 8-week old female C57BL/6 mice at an energy dose of 50 J/cm2, twice a day, for 10 consecutive days. The red, green, and blue groups represented wavelengths of 630 nm, 525 nm, and 410 nm, respectively. Untouched group (UT) was not exposed to LED light and served as the untreated control. Tear volume, tear film break-up time (TBUT), and corneal fluorescein staining scores were measured on days 1, 3, 5, 7, and 10. Levels of interferon (IFN)-γ, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were measured in the cornea and conjunctiva using a multiplex immunobead assay at day 10. Levels of malondialdehyde (MDA) were measured with an enzyme-linked immunosorbent assay. Flow cytometry, 2’7’-dichlorofluorescein diacetate (DCF-DA) assay, histologic analysis, and terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) staining were also performed.
Results :
TBUT of the blue group showed significant decreases at days 7 and 10, compared with the UT and red groups (all p < 0.05). Corneal fluorescein staining scores significantly increased in the blue group when compared with UT, red, and green groups at days 5, 7, and 10 (all p < 0.05). A significant increase in the corneal levels of IL-1β and IL-6 was observed in the blue group, compared with the other groups. The blue group showed significantly increased reactive oxygen species production in the DCF-DA assay compared to the UT, red and green groups (all p < 0.01) and increased inflammatory T cells in the flow cytometry compared to the UT group (p = 0.023). A significant increase in the density of TUNEL positive cells was identified in the blue group compared with that in the other groups.
Conclusions :
Overexposure to blue light with short wavelengths (410 nm) can induce oxidative damage and apoptosis to the cornea, which may manifest as increased ocular surface inflammation and resultant dry eye
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.