ENVIRONMENTAL STRESSORS AND THE EYE

Of all our senses, the most valued is sight. The eye, by virtue of its function in vision, must be in contact with the external environment. The cornea admits light, which is fine-focused by the lens into images and passes through aqueous and vitreous humors before reaching the retina. All of the component parts of the eye are susceptible to environmental stresses, depending on whether direct or indirect effects are involved, because of its external exposure. Indirect effects can arise when, for instance, one component of the eye influences another, either by (1) damaging lipid peroxides originating in the degenerating retina, causing damage to the lens posterior; – 4] or (2) immune damage to the lens via the aqueous humor from plasma antibodies to lens proteins. Direct effects can occur when toxic substances or physical trauma contact the eye surface, damaging the cornea. Penetrating wounds can damage the lens epithelium, and chemicals in the environment can diffuse across the cornea and aqueous humors to damage the lens epithelium or trabecular meshwork. Unfortunately, medications necessary for serious medical conditions, such as steroidal anti-inflammatory drugs, can have damaging side effects on the lens or cause a harmful elevation in intraocular pressure. Nutritional influences can also