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Age Related Macular Degeneration
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What is Age Related Macular Degeneration or ARMD?
Age related Macular Degeneration (ARMD) is a disease that causes progressive degeneration of the macula. Macula is the central part of the retina that allows us to see fine details. Many people develop Macular Degeneration as part of body’s natural ageing process. This condition, which is the commonest cause of blindness in the Western World after the age of 65, is now becoming common in our country too. In the past, treatment for ARMD was limited but extensive research on the subject has made its management possible, thereby helping the elderly retain their vision and improve their quality of life. |
Forms of Macular Degeneration
The two most common types of age related macular degeneration are:
- Dry Macular Degeneration (atrophic): This form is the more common form of the disease and accounts for 90% of all ARMD. It is caused by ageing and thinning of the tissues of the macula. Vision loss is usually gradual and may take years. Low vision aids may help the patient to do reading and near vision work.
- Wet Macular Degeneration (exudative): This form is characterized by development of abnormal blood vessels beneath the retinal pigment epithelial layer known as choroidal neovascularization (CNV). These vessels can bleed and eventually cause scarring (disciform scar), leading to a rapid and severe loss of central vision. The progression of wet ARMD is generally fast and causes profound loss of central vision in weeks to months. Hence, wet ARMD needs to be treated as early as possible.
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Fundus Photography showing Dry ARMD
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What Are the Symptoms of Macular Degeneration?
Early stages of Macular Degeneration may not cause decrease in vision. Sometimes only one eye loses vision while the other eye continues to see well for many years. The condition may be hardly noticeable in its early stages. But when both eyes are affected reading and close work can become difficult. You may experience one or more of the following symptoms.
- Straight lines look distorted, especially at the centre of the visual field
- Colors appear dim
- Words on a page look blurred
- A dark or empty area appears in the centre of vision
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Fundus Photography showing Wet ARMD
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Check your Central Vision with the Amsler Grid
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| The Amsler Grid is used to test the macula, the central part of the retina responsible for vision. It consists of a grid made of evenly spaced horizontal and vertical lines with a small dot in the center for fixation. To perform the test, follow the instructions given below. |
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- Hold the grid 30 cm from the eye
- Close one eye
- Focus on the dot in the center of the grid
Answer the following questions:
- Can you see the corners and sides of the square?
- Do you see any wavy lines?
- Are there any dark or missing areas?
If the lines of grid do not look straight or areas appear missing or distorted, please get your eyes checked by a retina specialist.
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Progression of Macular Degeneration
If there is macular degeneration in one eye, then the fellow eye is at high risk of developing macular degeneration as well. The risk of the fellow eye developing macular degeneration is reported to be 38% - 55%. Nutritional supplements with Vitamin C, E, beta carotene and zinc can lower the risk of developing advanced stage ARMD. Smoking may increase your chances of developing ARMD.
Treatment options for ARMD
a. Laser Photocoagulation and Photodynamic Therapy (PDT)
Although accounting for 10% of all cases of ARMD, Wet ARMD causes severe vision loss. Recent studies have proven that selected patients have much less chance of significant visual loss if they are treated by Laser photocoagulation (Hot Lasers) than if they are not treated. Only 20% of the patients of Wet ARMD can be treated with Laser photocoagulation.
PDT is a type of cold laser which is used in patients on whom the neo vascular membrane is below the centre point of the eye (fovea i.e. sub foveal). The aim of this treatment is to stabilize the existing vision, but vision improvement occurs in less than 5% of the patients following the treatment.
b. Anti – VEGF Treatment
The latest development for treating Exudative ARMD are specific drugs which target a specific chemical that is critical for causing abnormal blood vessels to grow under the retina. This chemical is called vascular endothelial growth factor (VEGF). Anti - VEGF drugs block the trouble causing VEGF, reducing the growth of abnormal vessels and slowing their leakage.
These drugs can even partially reverse the process of deterioration in up to 30 – 40 % of patients.
c. Combination Therapy
Lot of patients of ARMD requires combination treatment which includes treatment with laser/PDT and VEGF Inhibitors. Let your ophthalmologist decide what is best for your eye.
d. Low Vision AIDS
In advanced stages of ARMD low visual devices like stand or handheld magnifiers help in making the day to day activities easier.
However, despite advanced medical treatment, some patients with Macular Degeneration will still experience vision loss because the problem in these therapies is that they need to be repeated at monthly or bi-monthly intervals depending on response. Further research is on to develop treatment modalities to help such patients.
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