The macula is the part of the retina, which provides us with central vision and allows us to see fine detail, such as recognizing a face, reading, or watching television. Macular Degeneration is a condition in which the macula gets damaged. It is often related to aging, and is commonly referred to as Age-related Macular Degeneration (AMD). The late stage, associated with vision loss, is the most common cause of irreversible blindness in people over the age of 50. It affects the central vision, especially while reading.
Most often vision loss starts in one eye. Because the healthy eye compensates for the loss of vision in the damaged eye, macular degeneration may initially go unnoticed. In many cases it will ultimately affect vision in the other eye as well.
Dry AMD: The retina becomes thinner (atrophic) and stops functioning. This may cause some people to detect “blank” areas in their central vision. The vision loss due to this Dry AMD is not very severe as compared to the wet AMD. While there is no treatment available for people with dry AMD, various low vision aids are available to help these people see well and perform daily activities.
Wet AMD: Abnormal blood vessels grow under the macula. These abnormal vessels leak fluid and blood, and thus cause swelling and scar tissue formation, leading to distorted vision and severe vision loss.
The vision lost due to AMD is generally irreversible, and the treatment methods try to preserve vision but can not improve vision. Hence it is important to detect this disease at an early stage, before it has caused significant vision loss.
In the early stages of AMD, a person's vision may become blurred or distorted. A retinal examination, with the help of special tests like Fluorescein Angiography etc. can help the eye specialist to diagnose the condition. Since many times the patient may not notice the initial distortion or blurring of vision, the key to preventing vision loss due to AMD is regular eye examinations for patients above 40 years of age.These regular checkups are also useful in detecting other potentially serious diseases like Glaucoma.
Untreated, AMD is known to progress and lead to further loss of vision, the rate of deterioration being faster in the wet type. Antioxidants and Multivitamin capsules may have a role in preventing or decreasing the speed of progression of the disease. In wet AMD, additional methods of treatment are required to arrest or at least retard the progression of the disease. Many methods have been tried and are being developed. The best suited treatment modality is decided by the eye specialist after discussing with the patient. One may need to use a combination of various therapies. The most popular and established modes of treatment are:
Conventional Laser: burns the abnormal blood vessels and thus stops the leakage. However, since it also damages the normal retina structures, it may itself lead to decreased vision. Hence, it is suitable only in selected cases where the new vessels are not very close to the central macular area.
Anti-VEGF agents : The available agents are Lucentis, Avastin, and Macugen. When injected into your eye (intravitreal), it works by inhibiting the growth of abnormal blood vessels in the back of the eye. By blocking the stimulus, it can stop the blood vessels leaking and growing. In many cases it actually causes the blood vessels to regress, and even improves vision.
Photo Dynamic therapy (PDT): involves the injection of a special dye that binds to the abnormal blood vessels. After the injection, this area is treated by a special laser which selectively destroys the abnormal blood vessels without much damage to the normal structures.
Transpupillary Thermo-Therapy (TTT): uses a special delivery system of Infra red laser which heats up the abnormal blood vessels and causes its closure, without much damage to the normal retinal structures. More than one sitting of these treatments may be required. The aim of the treatment is to try to preserve the vision and not to improve the vision. This technique is not often used nowadays, and may find use in some selected cases only.
A special Amsler Grid is given to the patient to monitor the progress of the disease. With timely and proper treatment, and regular follow ups, majority of the patients are able to maintain useful vision to perform their daily activities and lead a socially productive life.