Ultraviolet light exposure and its penetrance through the eye in a porcine model

Abstract

Aim: To determine the amount of ultraviolet (UV) light irradiance that various layers of the eye receive as sunlight passes through the eye, and to investigate the protective benefits of UV light-blocking contact lenses.

Methods: Twenty-four porcine eyes were prepared in one of three ways: isolated cornea, cornea and lens together, or whole eye preparation. UV light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye structure. In the whole eye preparation, a hole was placed in the fovea to measure light as it passed through the vitreous. Subsequently, UV-protective contact lenses were placed over the structures, and UV light penetrance was measured. Measurements of UV light exposure were taken outdoors at various locations and times.

Results: Cornea absorbed 63.56% of UV light that reached the eye. Cornea and lens absorbed 99.34% of UV light. Whole eye absorbed 99.77% of UV light. When UV-protective contact lenses were placed, absorption was 98.90%, 99.55%, and 99.87%, respectively. UV light exposure was dependent on directionality and time of day, and was greatest in areas of high albedo that reflect significant amounts of light, such as a beach.

Conclusion: Cornea absorbs the majority of UV light that reaches the eye in this model. UV-protective contact lenses reduce UV exposure to the eye. Locations with high albedo expose the eye to higher levels of UV light.

Keywords: contact lens; cornea; lens; penetrance; ultraviolet light.

Figure 1. UV light penetrance through eye structures with and without UV blocking contact lenses.