Abstract
Purpose :
The relationship between UV light and damage to the eye has been established, but the degree to which UV light penetrates the eye and what structures absorb the most UV light was previously unknown. The aim of our study is to quantify UV light exposure in the eye and to determine the amount of UV light irradiance that various layers of the eye receive as light passes through the eye. Additionally, protective benefits of UV light blocking contact lenses are investigated.
Methods :
Thirty pig eyes were prepared in one of three ways: isolated cornea, cornea plus lens, and whole eye preparation, in which a hole was made in the fovea to measure light as it passed through the vitreous. A UV-A/B light meter designed to detect UV light between 280-400nm wavelengths was used to measure irradiance of the sun outdoors at baseline. UV light irradiance was then measured after the UV light meter was covered by one of the eye preparations in order to measure UV light penetration in various eye structures. A UV-protective contact lens was placed over the eye structure, and UV light penetrance was measured. Additionally, measurements of UV light exposure were taken outdoors at various locations and times throughout the day as the sun angle changed.
Results :
Cornea absorbed 63.56% of UV light that reached the eye. Cornea and lens absorbed 99.35% of UV light. The whole eye absorbed 99.77% of UV light. When UV-protective contact lenses were in place, the absorption was 98.9%, 99.55%, and 99.87%, respectively. Additionally, UV light exposure to the eye was highest at mid-morning and mid-afternoon, and the exposure was greatest in areas of high albedo.
Conclusions :
Cornea absorbs the majority of UV light that reaches the eye in this model. UV-protective contact lenses reduced UV exposure to the eye by absorbing UV light. Areas with high albedo during mid-morning and mid-afternoon exposed the eye to the highest levels of UV light. With anterior structures of the eye absorbing the most UV light and with the effectivity of the UV-protective contact lenses, protecting the eye with UV-blocking contact lenses could reduce the risk of UV light mediated ocular aging. Further investigation of UV light penetrance of eye structures and the effectiveness of UV-protective contact lenses is needed to better understand the impact of UV light on individual structures of the eye.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.