Inherited retinal disorders
There are many inherited retinal diseases. These disorders often affect the macula, which is the part of the retina responsible for sharp central vision used for reading and driving.
These diseases tend to run in families (that is, be familial), happen on both sides of the body (bilateral), and are often symmetrical (occur in the same way on both sides). Inherited diseases can cause severe vision loss and are often slowly progressive.
Some hereditary diseases, such as retinitis pigmentosa, tend to cause a more generalized destruction of the entire retina. Although there are visual aids to help people with these diseases, there is, at this point, no satisfactory treatment of the diseases themselves.
A study in the Archives of Ophthalmology reported that Vitamin A palmitate (15,000 IU per day) helped to preserve retinal function in patients with retinitis pigmentosa. A subsequent study reported that an omega-3 fatty acid called docosahexaenoic acid (DHA) provided a benefit that was limited to those patients starting Vitamin A palmitate for the first time. In these patients, DHA supplementation slowed the course of retinitis pigmentosa for the first two years in patients also being started on Vitamin A. It is important to always consult a physician before engaging in vitamin supplementation.
An additional study reported that patients eating a diet rich in omega-3 fatty acids such as salmon, tuna, mackerel, herring, or sardines have a 40% to 50% slower annual rate of visual loss than patients with a low omega-3 rich dietary intake.