Macula is the highly light sensitive part of the retina located at the far back of the eye cavity. It enables the sharpest possible vision, and the greatest possible focus in humans when looking straight ahead. While you can still distinguish objects clearly looking sideways, the image will not be as crisp and clear.
It is unclear why macular degenerations happen more frequently than degenerations or diseases in other parts of the retina. It is unclear whether the much higher density of the light receptors, cones and rods, has something to do with it. However, the fact is that the degeneration of the macula is the leading cause of blindness in people over 60 years old, and in one form or another affects more than 10% of the population over 70 years old.
Macula degeneration takes on several possible forms, mostly based on what age the onset of the degeneration starts, and what the microscopic as well as genetic footprints of the disease are. The common symptoms in all of these diseases have to do with distorted central vision – the objects appear blurry, straight lines become wavy, it becomes difficult for one to focus. Also, grey spots may appear in the center of the view. We will enlist the most common types of the degeneration of the macula here, and report on the current status of the availability of the cure and/or treatment.
Juvenile macular degeneration
Also known as juvenile macular dystrophy and Stargardt disease after the ophtalmologist that discovered this disease over a hundred years ago, juvenile macular degeneration usually shows initial signs between the ages of 6 to 20. Microscopically it manifests itself as the lipid (fatty) deposits underneath the protective “RPE” layer in the retina. As the deposits grow, the RPE gets damaged and the nutrients flow to the light receptors above the RPE layer is diminished, and the loss of vision ensues.
There is currently no cure or treatment for this disease. However, embrional stem cell research has been able to discover ways to regenerate sufficient amounts of the RPE layer, which can be surgically implanted to replace the damaged parts of the RPE layer. Clinical studies in humans are underway to confirm that the vision degeneration can be halted through the implantation, and, moreover, that there are no show-stopping side effects such as excessive scarring.
If the clinical trials are successful, the embrional stem cell RPE layer replacement will likely be recommended for people in earlier stages of juvenile macular degeneration, when the RPE layer may be damaged but the light receptors are still functional.
To take the maximum advantage of the procedure, it is advisable to attend genetic counseling to figure out if you have a predisposition for the juvenile macula degeneration. If so, it is important to see an ophthalmologist (the eye doctor) and get diagnosed early.
Dry age-related macular degeneration
Similar to juvenile macular degeneration, dry age-related macular degeneration, or dry AMD, also manifests itself as deposits under the RPE layer in the retina. Dry AMD usually onsets at the advanced age, and is the leading cause of blindness in adults.
There is currently no cure or treatment for dry AMD, however, significant research has been performed over the past 20 years, and a possible treatment, or drug is being produced which will affect and prevent the pathway in which the sub-RPE deposits are created, thereby at least halting the progress of the disease and prevent blindness to progress.
Wet age-related macular degeneration
In wet AMD, blood capillaries from the capillary layer underneath the RPE layer grow through the RPE and embed themselves among the light receptor cells, the cones and the rods. The blood capillaries also burst and create blood deposits that cut the supply of nutrients to the light receptors and cause the deterioration and death of light receptors.
Currently, there are several options to stop the progress of the disease. Some involve a powerful laser that burns away of the blood deposits. Others involve a drug injected in the blood system, and a weak laser activating the drug in the retina. The drug, when activated, is able to seal the leaking capillaries and prevent further build up of blood deposits, thereby halting the progress of the disease. This last treatment is known as photo dynamic therapy.