of the eye, how to improve its health and see better
September 10 2017 by Ray Sahelian, M.D.
The retina is located in the back of the eye. Light enters the pupil, is focused and inverted by the cornea and lens, and is projected onto the back of the eye where the retina is located. The retina has seven layers of alternating cells and processes which convert a light signal into a neural signal. The actual photoreceptors are the rods and cones, but the cells that transmit to the brain are the ganglion cells. The axons of these ganglion cells make up the optic nerve, the single route by which information leaves the eye. For natural ways to improve eyesight see the article for healthy ways for better vision.
Carotenoids found in the retina
The retina is unique in the human body in containing three xanthophyll carotenoids; zeaxanthin, meso-zeaxanthin and lutein. See Zeaxanthin astaxanthin information. The retina also has a high amount of a fatty acid called DHA. Dietary sources of DHA include fatty fish. Fish and fish oils have the fatty acids EPA and DHA. EPA is able to convert into DHA. Taking fish oil capsules can help improve vision.
Surv Ophthalmology. 2013. Iron, zinc, and copper in retinal physiology and disease. The essential trace metals iron, zinc, and copper play important roles both in retinal physiology and disease. They are involved in various retinal functions such as phototransduction, the visual cycle, and the process of neurotransmission, being tightly bound to proteins and other molecules to regulate their structure and/or function or as unbound free metal ions. Elevated levels of "free" or loosely bound metal ions can exert toxic effects, and in order to maintain homeostatic levels to protect retinal cells from their toxicity, appropriate mechanisms exist such as metal transporters, chaperones, and the presence of certain storage molecules that tightly bind metals to form nontoxic products. The pathways to maintain homeostatic levels of metals are closely interlinked, with various metabolic pathways directly and/or indirectly affecting their concentrations, compartmentalization, and oxidation/reduction states. Retinal deficiency or excess of these metals can result from systemic depletion and/or overload or from mutations in genes involved in maintaining retinal metal homeostasis, and this is associated with retinal dysfunction and pathology. Iron accumulation in the retina, a characteristic of aging, may be involved in the pathogenesis of retinal diseases such as age-related macular degeneration (AMD). Zinc deficiency is associated with poor dark adaptation. Zinc levels in the human retina and RPE decrease with age in AMD. Copper deficiency is associated with optic neuropathy, but retinal function is maintained. The changes in iron and zinc homeostasis in AMD have led to the speculation that iron chelation and/or zinc supplements may help in its treatment.
Retinal vessels and cardiac health
The width of the small veins and arteries in the eye may be a good indicator of a middle aged person's chances of dying from coronary heart disease. Researchers analyzed the caliber of the vasculature of the retina in men and women over the age of 49. This was done by looking at detailed photographs of the retina, measuring the diameters of the small arteries (arterioles) and small veins (venules), and calculating their ratio, known as the AVR. Arterioles and venules are small branches of main arteries and veins, and their condition in the retina reflects the general state of the smaller blood vessels in the body, or microcirculation. Deaths from coronary heart disease doubled if the venules were wider. Wider venules have been linked to several risk factors for coronary heart disease, including smoking, systemic inflammation, high total cholesterol and obesity. In women in this age narrower arterioles in the retina were also associated with a 50% increased risk of dying from coronary heart disease. Signs in the small vessels of the retina appear to be independent predictors of the risk of death from coronary heart disease. Retinal photography may be a useful non-invasive method of assessing this risk.
Blood vessels in retina and risk of dementia and stroke
Examining the blood vessels in the retina of the eye may give a clue to the mental status of elderly people and their risk of developing dementia. The presence of retinal damage, or retinopathy, is a marker of early damage to the blood vessels in the brain, and is a predictor of future stroke risk.
Retina Cell Transplant?
2006 - British and American scientists have restored vision in blind mice by transplanting light-sensitive cells into their eyes in a breakthrough that could lead to new treatments of human eye diseases. The mice suffered from eye damage called photoreceptor loss which occurs in macular degeneration, the leading cause of sight loss in the elderly, and other eye disorders. Instead of using stem cells, which could form into any cell type, the scientists transplanted cells that had reached a later stage of development toward becoming photoreceptor cells. The scientists believe further research could lead to the first human retina cell transplants for people with blinding diseases within a decade. Photoreceptors are specialized light sensitive cells that line the back of the eye and are essential for sight. In eye diseases such as macular degeneration, the cells are destroyed. Researchers had thought that the mature retina, the part of the eye that senses light and forms images, did not have the capacity for repair. Researchers used precursor cells that are already programmed to become photoreceptors but are not quite there yet was the key to successful transplantation. Scientists have recently found cells on the margin of the retina in humans which have stem-cell like properties and could potentially be grown in the lab to become photoreceptor precursor cells for treatment. The findings by MacLaren and scientists from the Institute of Ophthalmology and the Institute of Child Health in London and the University of Michigan Medical School in the United States are published online by the journal Nature.
Q. Are there any nutrients that help the retina?
A. Yes, there are. I would say lutein, zeaxanthin, EPA and DHA are at the top of my list.
Your research department might be interested in the latest report I got from my retina specialist when I saw him in May 2010. Due to presumed ocular histoplasmosis, I have laser scars on the retina in both eyes, loss of peripheral vision in both eyes, and loss of central vision in the left eye. But together with both eyes I'm doing very well and just want you to know that I feel that your product is a large part of the reason why. After enduring 18 monthly injections of the drug Avastin in my left eye due to abnormal vessels bleeding, in May of 2009 I read on the American Foundation for the Blind message board that someone had used curcurmin / turmeric for a similar condition with very good results. So in May 2009 I began taking three capsules daily of your product. Since that time, now almost a year ago, the doctor has been amazed and pleased with my progress. I've not needed any more Avastin shots and instead of being seen monthly, the doctor began seeing me every four months. The doctor said that I did not have to come back until SIX months! There is no fluid, and no blood present in the left eye, and the doctor mentioned that it is "curious" that where there would normally be grey areas where the vessels had been bleeding, now there is no evidence of them at all. He instructed me to continue doing exactly what I've been doing. FYI, I have posted on the American Foundation for the Blind's message board a link to your website so that others might read of my experience and have a source for the supplement if they wish to try it. Thank you again, and keep up the excellent work!
Retinoblastoma affects 1 in 15,000 children
Retinopathy of prematurity, or ROP — The same abnormal growth of blood vessels behind ROP triggers two leading causes of blindness in adults: diabetic retinopathy and age-related macular degeneration. These diseases destroy the retina, the eye's innermost layer, which harbors a higher percentage of certain fats than other organs. Eat lots of salmon, rich in omega-3s, and your retina will show it. Eat mostly hamburgers, and your retina will harbor more of a different fatty acid, omega-6s. The retina's composition actually changes with diet.