Rhodopsin, or retinal purple, is the light-sensitive pigment present in the cells of the retina and responsible for night vision and the eye's sensitivity to light. The retina is made up of two types of cells, cones and rods. The cones are rather sensitive to light and the rods to darkness. Rhodopsin is mainly used by rods and is useful for night vision.
When light hits the retina, rhodopsin instantly breaks down into retinal and opsin. It is the splitting of these two molecules, of which rhodopsin is formed, which triggers a signal sent to the brain's vision center, and which makes it possible to produce images in the dark. Then, retinal and opsin recombine into rhodopsin. It is during this period of reconstitution that the ability to see in the dark is disturbed. This period increases with age and leads to a progressive decrease in night vision.
The cyanidins are purple pigments in the flavonoid family. They are recognized as powerful antioxidants and protect the retina from virulent attacks by free radicals, but above all they increase the speed of reconstitution of rhodopsin in the night vision process.
There are other pigments that are essential to the good health of the eye and to the maintenance of the optimal vision process, these are the macular pigments. They form a protective layer that absorbs blue light and ultraviolet rays of the solar spectrum. It is important to know that blue light is charged with a very high energy level which, in the long term, can cause damage to the retina and the lens. The most sensitive area of the retina, where the cells are most concentrated, is called the macula. With age, when the macula is damaged, it is called macular degeneration (AMD). If it is the lens that is attacked, it is called a cataract.
Important substances for our eyes
Once again, nature provides us with protective substances that are found especially in algae. These are pigments such as lutein, zeaxanthin and astaxanthin, 3 extremely antioxidant carotenoids capable of neutralizing the destructive free radicals released when the energy of blue light interacts with the fragile tissues of the eye. They help to reconstitute the protective layer of macular pigments, thus reducing glare and improving contrast and visual acuity. Studies have clearly shown that the contribution of these substances increases the thickness of the protective layer of macular pigments and provides real protection against AMD.
It has also been proven that these substances play a crucial role in the prevention of cataracts by protecting the proteins of the lens against the aggression of ultraviolet light, as they act as a sort of natural sun filter and improve the eye's reactions to glare.
The current working conditions (often in front of a screen) tire the eye muscles enormously and they weaken over time. Bright lights and numerous visual stimuli at close range lead to an increase in accommodation speed, i.e. an increase in the time required for the eye to focus when going from near to far vision or vice versa. Sensitivity to glare or depth perception, as well as eye irritation and fatigue are very common in people who spend 4 to 7 hours in front of a screen. In this case, it is better to use astaxanthin, a carotene present in algae, but also found in the flesh of fish, which is what generally gives them their pink color.
Supplementation with astaxanthin preserves accommodative function, reduces eye fatigue, and improves blood flow to the retina. Ocular tissues are rich in lipids, as are many other cell membranes in the body. Astaxanthin being very liposoluble will present a strong affinity with all these tissues. The anti-inflammatory qualities of astaxanthin are also very interesting, as they reduce the formation of blood neo-vessels observed in the advanced stages of AMD. In addition, it slows the destruction of retinal cells in the case of intraocular tension characteristic of glaucoma, which can be another cause of blindness in the elderly.