Peripheral focusing of light by the anterior eye may provide a unifying concept to explain the location and etiology of sun-related eye conditions (ophthalmohelioses). Using a bovine eye model, along with computer-assisted ray-tracing techniques to model limbal focusing, we demonstrated a correlation between the locations of the foci of scattered incident light (resulting in a 20-fold concentration of light at the limbus) and the usual locations of pterygium and cortical cataract. These findings suggest the need for improved ocular protective devices, particularly ones that provide lateral protection of the eye against the increased ultraviolet insolation resulting from thinning of the ozone layer.