The eye is on the one hand dependent on visible light energy and on the other hand can be damaged by these and the contiguous ultraviolet (UV) and infrared wavelengths. Diseases of the eye in which sunlight has been implicated have been termed the ophthalmohelioses, and these conditions pose a significant problem to the eye health of many communities. The ophthalmohelioses have a tremendous impact on patients' quality of life and have significant implications on the cost of health care. Although cataract is not entirely caused by insolation, it now seems certain that sunlight plays a contributory role—cataract extraction is one of the, if not the most, commonly performed surgical procedures in many societies. Pterygium, typically afflicting a younger population, adds a tremendous burden, both human and financial, in many countries. We review evidence that peripheral light focusing by the anterior eye to the sites of usual locations of pterygium and cataract plays a role in the pathogenesis of these conditions. Recognition of the light pathways involved with foci at stem cell niches has directed our investigations into inflammatory and matrix metalloproteinase-related pathophysiologic mechanisms. An understanding of the intracellular mechanisms involved has provided some insight into how medical treatments have been developed for the effective management of ocular surface squamous neoplasia. The concept of peripheral light focusing has also provided direction in the prevention of these diseases. This has resulted in improved sunglass design and the further development of UV-blocking contact lenses. With the development of ocular UV fluorescence photographic techniques, we have been able to demonstrate preclinical ocular surface evidence of solar damage. Evidence that diet may play a role in the development of certain conditions is reviewed. The conundrum of the public health message about solar exposure is also reviewed, and in this context, the potential role of vitamin D deficiency is summarized. The eye may play a role in the development of individualized assessment techniques of solar damage, perhaps allowing us to provide better advice to both individuals and populations.
From the Department of Ophthalmology, University of New South Wales, Sydney, Australia.
Disclosure: The author discloses that he is the inventor of US Patent 7,217,289: Treatment of photic disturbances in the eye, US Patent 7,846,467: Ocular scaffold for stem cell cultivation and methods of use, US Patent application 20060204474: Treatment of epithelial layer lesions, US Patent application 20050287115: Treatment of ocular lesions; is a consultant to Allergan, Inc in the area of medical treatment of pterygium and dry eye and has received research funds and travel support; receives royalties from Eagle Vision Inc in relation to a dry eye product; and has been a consultant to Johnson and Johnson Vision Care Inc and has received research funds and travel support.
Address correspondence and reprint requests to Minas Coroneo, M.Sc., M.S., M.D., Department of Ophthalmology, Prince of Wales Hospital, High St. Randwick, NSW 2031, Sydney, Australia; e-mail: M.Coroneo@unsw.edu.au
Accepted May 6, 2011.