Age-related cataract and macular degeneration: Oxygen receptor dysfunction diseases

Age-related cataract and age-related macular degeneration (AMD) is the leading cause of vision impairment and blindness in developing and developed countries, respectively. Oxidative stress and oxidation products have been verified to play important roles in these two aging diseases. Recent research has demonstrated that there are significant oxygen gradients in the eye. Therefore, we propose a new hypothesis that these two diseases could be summarized as oxygen receptor dysfunction diseases of which the main points are as follows. Oxygen in the retinal and choroidal vasculature is transferred into the vitreous cavity by a special switching valve or oxygen receptor that might exist in the internal limiting membrane, vascular endothelium or posterior vitreous surface. It is then transported from the posterior segment to the anterior segment by vitreous collagen fibrilla networks, which work similar to a gas pipeline. Posterior vitreous detachment is the starting point of these two diseases by inducing formation of the local hyperoxia region, which results in the occurrence of age-related cataract and macular degeneration. Thus, an innovative anti-oxidative therapy should be added to the traditional treatment of age related macular degeneration. Some associated experimental and clinical approaches are suggested in our paper to test this hypothesis.