The retina is part of the central nervous system (CNS) and the only that can be imaged directly.
The rods are more numerous, around 120 million, than the cones (6-7 million). The former are situated at the periphery of the retina, while the cones are concentrated in the central yellow spot known as the macula-fovea centralis. Despite of being more sensitive than the cones, the rods are not sensitive to color. The retinal pigment epithelium (RPE) is the brown pigmented cell layer outside the neurosensory retina (rods & cones) also called neuroepithelium. RPE nourishes retinal visual cells, it supplies omega-3 fatty acids and glucose, it protects the retina from too much incoming light, and it produces substances to help strengthen the choroid and retina.
Retinitis pigmentosa is the common name applied by Doctor Donders (Dutch ophthalmologist) in 1857, for a group of rare eye diseases consisting of several related, distinct, hereditary, progressive retinal dystrophies in which its photoreceptors and the pigment epithelium underneath them are deteriorating. The dystrophy process begins with changes in pigment and damage to the small arteries and blood vessels that supply the retina. Rods, responsible for vision in low light and used for peripheral vision, are the first ones which are affected causing night blindness and gradual narrowing of the field of vision. It ultimately results in tunnel vision with cones being affected as well. The cones provide vision in bright light, including color vision. RP is usually bilateral and seldom leads to total blindness. Some kinds of RP are inherited others are sporadic with no family history at all.
The first sign of retinitis pigmentosa is usually a loss of night vision (nyctalopia), which becomes apparent in childhood. Later, blind spots develop in the side (peripheral) vision. Ultimately, these blind spots merge to produce tunnel vision. The disease progresses over years or decades to affect central vision, which is needed for reading, driving, and recognizing faces. So, symptoms can start as early as childhood, but side effects may not be obvious until early adulthood. Occasionally, the disorder progresses slowly and is found during eye routine examination. Other symptoms include: cataracts, loss of central vision, open-angle glaucoma (3% of patients).
Your permanent goal should be to slow down the retinal degenerative process and the thinning of its blood vessels. The foods I describe here will help to preserve and re-activate your retina.
