Macular Degeneration
Background Information
Age-related macular degeneration (ARMD) ARMD is caused by hardening of the arteries that nourish the retina. This deprives the sensitive retinal tissue of oxygen and nutrients that it needs to function and thrive. As a result, the central vision deteriorates. Macular Degeneration is the most common cause of visual impairment in the UK and is generally related to age - it is sometimes referred to as 'wear and tear' in the eye.
The macula is the part of the retina responsible for seeing fine detail in the centre of the field of vision. Whenever a person is looking directly at an object it is the macula that receives the image. When Macular Degeneration occurs, it is detailed central vision that suffers. Peripheral vision i.e. the field of vision, is unaffected. This means the person will often see best 'out of the corner of the eye', rather than by looking straight at the object of interest.
Macular Degeneration varies widely in severity. In the worst cases, it causes a complete loss of central vision, making reading or driving impossible. For others, it may only cause slight distortion. Fortunately, macular degeneration does not cause total blindness since it does not affect the peripheral vision.
Different types of Macular Degeneration
There are two main types, Dry and Wet Macular Degeneration. The dry type is generally mild, very slow to worsen and not severely disabling. It does not respond to any active treatment and is best managed by better lighting and magnifying aids. The wet type starts with central distortion of sight and can progress catastrophically to loss of all central vision in the affected eye. Strangely it seems to represent an attempt by the body to repair the damage and it does sometimes respond to prompt treatment: sudden or rapid loss of central vision should lead to immediate attendance at the local emergency eye centre.
Causes of Macular Degeneration
Macular Degeneration may be caused by variety of factors. Genetics, age, nutrition, smoking, and sunlight exposure may all play a role.
Signs and Symptoms
- 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.)
Detection and Diagnosis
Eye physicians usually diagnose ARMD. Vision testing, Amsler Grid test, Ophthalmoscopy, Fundus Photography and Fluorescein angiogram are some common tests performed during a retinal exam.
Treatment
There is no proven medical therapy for dry macular degeneration. In selected cases of wet macular degeneration, laser photocoagulation is effective for sealing leaking or bleeding vessels. Unfortunately, laser photocoagulation usually does not restore lost vision, but it may prevent further loss.
Recently, photodynamic therapy has proven to be effective in stopping abnormal blood vessel growth in some patients with wet ARMD. This new type of laser treatment is far less damaging than laser photocoagulation and is the treatment of choice in many cases.
Early diagnosis is critical for successful treatment of wet macular degeneration. Patients can help the doctor detect early changes by monitoring vision at home with an Amsler grid.
Nutrition and 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 Age-related 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. Henshaws' Low Vision Clinic in Liverpool is run by specially trained staff to help visually impaired patients improve their quality of life. After a personalised consultation, they can recommend appropriate magnifiers, reading aids, practical tips, and many resources.
The main practical difficulties are likely to be in seeing fine details such as reading, writing, seeing people's features, sewing and crossing roads. Children and young people can also suffer from an inherited form of macular degeneration called macular dystrophy.
Henshaws Society for Blind People hosts a Liverpool Macular Disease group and a Manchester Macular Disease group at our accessible centres.
Disclaimer of Medical Liability
Whilst we have taken great care to gather correct information and to keep it current, we cannot guarantee its accuracy and completeness.
The information provided should never be considered a substitute for professional health care by a qualified doctor or other health care professional, which will be tailored to the patient's individual circumstances. Henshaws cannot take responsibility if you rely on this information alone.