The macula is the part of the retina, which provides us 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.
What are the types of Age-related Macular Degeneration (AMD)?
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.
Why is Early Detection important?
The vision lost due to AMD is generally irreversible, and the treatment methods try to preserve vision but may not improve vision. Hence it is important to detect this disease at an early stage, before it has caused significant vision loss.
How is Macular Degeneration or AMD detected?
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, OCT 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.
What are the Treatments available?
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. There have been many exciting developments in the treatment of Wet AMD with better results now. The best-suited treatment modality is decided by the eye specialist after discussing with the patient. The most popular and established modes of treatment are:
Intravitreal Injections: This is the exciting new development in which certain special medicines like anti-VEGF agents (Lucentis/Accentrix/Razumab, Eylea, Avastin etc.) are injected in small quantities within the eye to arrest the disease. The success rate for maintaining the vision is as high as 90% and in about 30% of cases, there is even an improvement of vision. However, the effect of these injections is not permanent and generally repeated injections (at 4- 6 weeks interval) may be required.
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.
Photo Dynamic Therapy (PDT): Involves the injection of a special dye in the veins and then performing a special laser which selectively destroys the abnormal blood vessels without much damage to the normal structures.
After advent of Intravitreal injections, PDT and Conventional lasers are used in selected cases in conjunction with intravitreal injections. 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. 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.