What is Age Related Macular Degeneration?
Macular degeneration is an age-related wearing out of the central retina, which is essential for detailed vision. It usually affects people above the age of 50 and has no cure although treatment is available.
The retina is a light-sensitive layer at the back of the eye. Light entering the eye is focused on the retina where it is converted into electrical signals. These signals are carried to the brain where vision is perceived. The macula is a small area at the centre of the retina that is highly sensitive to light and is responsible for sharp central vision (view of objects in the centre of your visual field). Degeneration of the macula can affect central vision making it difficult to carry out various activities.
What a patient with advanced macular degeneration sees
Types of aged macular degeneration
There are two types of aged macular degeneration: Dry and Wet.
Dry AMD: This type of aged macular degeneration occurs with accumulation of yellow deposits (drusen) under the retina which later increase in size and number. Loss of macular cells and vision occurs gradually.
Wet AMD: This type of AMD occurs due to the formation of abnormal blood vessels under the retina. These vessels bleed or leak resulting in swelling that damages the retina. Vision loss and macular degeneration occurs more rapidly with wet AMD.
What causes aged macular degeneration?
Aged macular degeneration may be caused by a variety of factors. Genetics, age, nutrition, smoking, and sunlight exposure may all play a role.
What are the symptoms associated with aged macular degeneration?
In the early stages of AMD, there are usually no symptoms. As macular degeneration progresses you will experience:
- Loss of central vision. This may be gradual for those with the dry type. Patients with the wet type may experience a sudden decrease of the central vision.
- Difficulty reading or performing tasks that require the ability to see detail
- Distorted vision (Straight lines such as a doorway or the edge of a window may appear wavy or bent)
How is aged macular degeneration diagnosed?
To diagnose aged macular degeneration, your doctor will perform a detailed eye examination which usually includes:
Visual acuity test: Determines how well you can read a chart from a distance with each eye
Dilated eye exam: The pupils are dilated with eye drops and a magnifying lens is used to examine the retina. Small yellow deposits under the retina are an early sign of macular degeneration.
Amsler grid test: When those with aged macular degeneration look at the Amsler grid, lines appear wavy or disappear.
Wavy lines on the Amsler Grid
Optical coherence tomography: Light waves are passed through the eye after dilating the pupils and used to obtain a high-resolution 3D image to clearly view the retina and its underlying layers.
Fundus photography: A retinal camera or low-power microscope used to obtain images of the retina and underlying tissues.
Fluorescein angiography: An imaging study of the blood vessels of the retina which are visualised with the help of a dye.
Nutrition and aged macular degeneration
Several recent studies have indicated a strong link between nutrition and the development of macular degeneration. It has been scientifically demonstrated that people with diets high in fruits and vegetables (especially leafy green vegetables) have a lower incidence of macular degeneration. More studies are needed to determine if nutritional supplements can prevent progression in patients with existing disease.
Tips for aged macular degeneration patients
If you've been diagnosed with AMD, making a few simple lifestyle changes could have a positive impact on the health of your retina.
- Monitor your vision daily with an Amsler grid. By checking your vision regularly, changes that may require treatment can be detected early.
- Take a multi-vitamin with zinc. (check with your eye physician for a recommendation). Antioxidants, along with zinc and lutein are essential nutrients, all found in the retina. It is believed that people with AMD may be deficient in these nutrients.
- Incorporate dark leafy green vegetables into your diet. These include spinach, collard greens, kale and turnip greens.
- Always protect your eyes with sunglasses that have UV protection. Ultraviolet rays are believed to cause damage to the pigment cells in the retina.
- Quit smoking. Smoking impairs the body’s circulation, decreasing the efficiency of the retinal blood vessels
- Exercise regularly. Cardiovascular exercise improves the body’s overall health and increases the efficiency of the circulatory system
These are a few tips to make reading easier
- Use a halogen light. These have less glare and disperse the light better than standard light bulbs.
- Shine the light directly on your reading material. This improves the contrast and makes the print easier to see.
- Use a hand-held magnifier. A drugstore magnifier can increase the print size dramatically.
- Try large-print or audio books. Most libraries and bookstores have special sections reserved for these books.
- Consult a low vision specialist. These professionals are specially trained to help visually impaired patients improve their quality of life. With a personalised consultation, they can recommend appropriate magnifiers, reading aids, practical tips, and many resources.
- Use a bright reading light
- Wear your reading glasses if appropriate
- Hold the chart approximately 14-16 inches from your eye
- Cover one eye
- Look at the centre dot
- Note irregularities (wavy, size, gray fuzzy)
- Repeat the test with your other eye
- Contact your ophthalmologist if you see any irregularities or notice any changes
What is the prognosis of aged macular degeneration?
Vision loss due to AMD is irreversible although it does not lead to total blindness. Timely treatment can minimise and slow down vision loss. The dry form progresses slowly while the wet form is associated with rapid macular degeneration which can lead to serious vision loss. Occasionally, dry AMD may lead to wet AMD. Those with AMD should have their eyes checked regularly.
What if aged macular degeneration goes untreated?
It is rare for untreated aged macular degeneration to progress to total blindness although you will suffer from significant disability due to poor or lost central vision.
What are the treatment options for aged macular degeneration?
The ‘dry’ form’s progression can be slowed using anti-oxidant supplements as highlighted by the famous AREDS2 clinical study.
The ‘wet’ form, where an abnormal blood vessel grows under the retina, can now be treated with anti-VEGF injections. The doctor’s in-room injection of an anti-VEGF drug for wet macular degeneration is performed with monitoring supported by both high-definition OCT and fluorescein angiography assessments.
Laser therapy and light-sensitive drugs can be used to destroy abnormal blood vessels under the retina. Vision-enhancing aids may be recommended as well.
Click to read more about Anti-VEGF treatments
Click to read more about Retinal laser treatments
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