The macula is the central section of the retina. The retina is a part of the eye that contains the photosensitive cells that are responsible in sending visual messages to the brain. The brain then interprets these electrical messages. The densest area of concentration of these photosensitive cells is located at the macula. The macular degeneration is impairment or loss of function of the macular zone that results to weakening and eventual death of the vital central vision. Thus the extensive development of blind spots.
Central vision is impaired while peripheral vision remains the same in macular degeneration. Symptoms are only obvious when the case is already advanced. This is because the brain adapts to the blind spots and fills in the details as it interprets the electrical messages sent to visual centers.
Most cases of appear in individuals aged 60 and above. This form of the disease is termed as AMD or Age-Related Macular Degeneration.
But contrary to what is originally known, macular degeneration also affects infants and children. This is caused by genetical factors, specifically gene mutation. This condition is called as Juvenile Macular Degeneration or JMD.
JMD is further subdivided into the following classifications:
Autosomal Dominant Hemorrhagic Macular Dystrophy- This disorder normally resembles the Sorsby's Fundus Dystrophy, except for the mutation of the gene TIMP-3.
Best's Vitelliform Macular Dystrophy- This condition ranks second after the Stargardt's disease and is normally a mild form of the macular degeneration. It is characterized with the egg yolk symptom that creates a drusen spot in the macula. This egg yolk spot will then break up, thus the term scrambled egg drusen. The degree of impairment on the central vision differs largely among different cases, even though they are related by blood. Some patients experience severe deterioration in the central vision, others don't.
Doyne's Honeycomb Retinal Dystrophy- This condition is known to have the same symptoms to that of the Adult Macular Degeneration that normally arise by patients second-half of life.
Sorsby's Fundus Dystrophy- With this type of JMD, symptoms are normally obvious during middle aged persons which includes neovascularization.
Stargardt's Disease- Is known to be the most common form of JMD. Symptoms associated with this type like scarring of the macula and visual acuity normally occur during childhood until the teenage years. Another variant of this type is the fundus flavimaculatus that develops during early adulthood.
Causes of macular degeneration are usually associated with the gene deficiency. Yet the root cause is yet to be determined. The dry form is considered to be the result of the thinning and aging of the macular tissues and the deposition of the pigment in the macula. It may also be the cause of both actions. In the wet form however, the primary cause may be the neovascularization or growth of new blood vessels underneath the retina and leak of fluid and blood. Leakage in return will "kill" the retinal cells that eventually create blind spots at the central vision.
Current studies concerning the macular degeneration are generally concerned on the effects of the faulty genes to vision. Macular degeneration is relatively new and there are many areas of studies that are yet to be researched and determined. This is the reason why there are still no concrete methods of diagnosing the existence of the disease and the process of treatment.
Robert Thatcher is a freelance publisher based in Cupertino, California. He publishes articles and reports in various ezines and provides macular degeneration resources on http://www.about-macular-degeneration.info.