Dr. Aragbaye
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Age related Macular Degeneration (AMD) is a very common form of visual impairment. About 1 in 10 people over age 65years have some level of AMD. More than 100,000 cases are recorded yearly in Nigeria.
Macular degeneration also known Age related Macular Degeneration (AMD or ARMD) is a medical condition which may result in blurred or no vision in the center of the visual field. Macular degeneration mainly affects central vision causing blind spots directly ahead.
There are two forms of AMD:-
- Dry form
- Wet form
The dry form is more common than the wet form, with about 85 to 90% of AMD patients diagnosed mostly with dry AMD. The wet form of the disease usually leads to more serious vision loss.
Stages of AMD
There are three stages of AMD defined in part by the size and number of drusenunder the retina. The stages are;
Early AMD: – Diagnosed by the presence of medium sized drusen. People with early AMD do not have vision loss.
Intermediate AMD: – There is a large drusen, pigment changes in the retina or both. Intermediate AMD may cause some vision loss, but most people will not experience symptoms.
Late AMD:- In addition to drusen, people with late AMD have vision loss from damage to the macular. Not everyone with early AMD will develop late AMD, However having late AMD in one eye means there is increased risk for late AMD in the other eye .
Macular degeneration doesn’t tend to cause total blindness because it doesn’t affect peripheral vision, but it can significantly interfere with daily activities such as driving, writing, cooking or fixing things around the house, it’s possible to have macular degeneration in only one eye or to have a more severe form of the diseases in one eye than the other. AMD is more common in white people than in black people. There is also a genetic risk.
Causes and risk factors
The exact cause of all forms of AMD is unknown, but the disease has been linked to both genetic and environmental factors.
Risk factors for AMD include
– Age (especially over 60)
– Family History
– Smoking
– Obesity, Nutrition
– Cardiovascular disease
Several genes have been linked to macular degeneration (such as the ABCA4gene) but research in this area is still in its early stage., There is presently no genetic tests that can diagnose AMD or predict who will develop it. Long term exposure to ultraviolet light, without proper eye protection is another risk factor.
Having light coloured eyes, being far sighted and having high levels of certain maker of inflammation in the body are also thought to contribute to higher risk for AMD.
Women are more likely than men to develop AMD, but this may be a factor of age rather than sex, as women live longer than men.
Symptoms and signs of AMD
Different forms of macular degeneration have slightly different symptoms. The basic symptoms of macular degeneration are:
Reduced or distorted central vision in one or both eyes
Reduced ability to see or differentiate colours
A blind or blurry spot in the field of vision
General haziness in the overall vision
The initial symptoms of AMD are not painful; and sometimes,when the condition begins in one eye, the stronger eye compensates,so changesin vision might not be noticeable
Diagnosis
To comfirm a diagnosis of macular degeneration, the eye doctor[specialist] would carry out these tests
1.Basic eye examination – visual acuity test; dilated eye examination.
- Amsier Grid – This is used in checking for defect in the center of vision.
- Fluorescein Angiography –This is used for checking abnormal blood vessels or other retinal changes.
- Optical Coherence Tomography –This test produces detailed cross-sectional images of the retina at the same time used to monitor response of retina to treatment.
Treatment
There is no cure for macular degeneration but several different approaches may be used to treat the condition and slow its progression
For intermediate dry macular degeneration a daily combination of vitamins and nutritional supplements has been shown to slow the progression of AMD.
For wet macular degeneration certain medicaments can stop growth of new abnormal blood vessels in the macular. Drugs used for this purpose include; Avastin; Lucentis
and Eylea (These drugs are in injection form).
Photodynamic therapy – Special light is used to activate a drug that can repair leaky blood vessels and prevent further damage to the macular. Multiple treatments may be necessary.
Laser photocoagulation – Laser is used to seal abnormal blood vessels.
The schanoth macula lens does not cure patients with dry AMD, it magnifies. Enable most patients to read again and distinguish small details, it does not affect distance vision.
Prevention
Certain steps can reduce the risk of developing macular degeneration and also help in managing the condition. These are:
– Getting routine dilated eye exams
– Quit smoking
– Regular exercise
– Healthy diet – diet full of antioxidants and nutrients
– Avoid ultraviolet and blue light which is understood to be harmful to the retina.
Maintain normal blood pressure and cholesterol levels.