The Relationship Between Free Radicals & Eye Damage

The idea that nutrition is important for the eyes is supported by the growing evidence of the danger of free radicals. Cataracts may be partially caused by free radical activity in the lens of the eye. Glaucoma researchers have begun to examine the relationship between free radical activity and the destruction of nerve tissue in the eyes. There is some evidence that if oxidation is counteracted by antioxidants, visual field loss due to glaucoma may be decreased.

Free radicals are fragments of molecules that are highly reactive - that is, they readily enter into chemical reactions with other substances because they have unpaired electrons spinning in their orbit. These electrons seek out other electrons to counterbalance them, and they may snatch an electron from an adjacent molecule or donate an unmatched electron from their own structures, in the process destabilizing the hapless compound that is their target. Many molecules and fragments of molecules may behave in this fashion, but the most dangerous are different forms of oxygen. When an oxygen molecule encounters another substance and snaps up or sheds one of its electrons, the resulting compound is said to be oxidized.

There is a positive side to free radicals. The reaction that allows the blood to carry oxygen to all of the body's cells involves free radicals. Free radicals are responsible for the immune system's ability to squelch pathogens; for the digestive system's ability to break down the food we eat; and for the nervous system's ability to fire up muscles, thoughts, and feelings. However, if there are more free radicals than the body can control, they may begin to attack the cells and cause serious damage.

Free radicals are generated in the course of various metabolic actions, such as the conversion of glucose (simple sugar) into cellular energy. The majority of the free radicals formed in this way are well contained and either reused or eliminated, but some of them escape, and researchers believe that these escaped free radicals may cause cellular damage.

Free radicals are also generated when iron, copper, and/or other naturally occurring metals react with oxygen. Normally, your body protects you from excesses of these elements, especially iron, by storing this element within the hemoglobin in red blood cells or by supplying a protein to ferry it from one place to another. But if something goes wrong with this system, or if there is simply too much of certain metals for the body to deal with, a chain reaction is set up that contributes to the production of free radicals that oxidize fats.

Oxidized fats are the type most likely to accumulate in the blood vessels, causing arterial damage. It is possible that many diseases are a result of free radical damage. Type II (adult-onset) diabetes and Parkinson's disease fall into this category. Certain cancers may be caused by reactions between free radicals and DNA that pave the way for uncontrolled replication of cells. Free radicals may also be behind joint pains by diminishing the quantity of lubricant in the joints or interfering with the elasticity of the tendons.