AGE RELATED EYE DISEASE
What is it?
The ageing eye can be affected in many different ways. One of them being the formation of a cataract or clouding of the normal human crystalline lens. The other common age related change affecting the eye is called Age related Macular Degeneration (AMD).
This condition usually affects people in the 6th or 7th decade of life, but may occur in the younger population.
This condition affects the area at the back of the eye, responsible for the central part of the vision, the macula (see “Eye anatomy”). Degeneration, or breakdown of this part of the retina causes loss of central vision, and is one of the most common causes of legal blindness in South Africa, and the world. Most patients retain some form of peripheral vision, but overall prognosis in late/advanced
AMD can be very poor.
What is “DRY” and “WET” AMD?
Dry AMD is the more common form and is also referred to as atrophic or non-exudative AMD. There is formation of drusenbeneath the macula that build up and eventually causes the macula to thin out as there is progressive breakdown of the photoreceptor cells within the retina.
Wet AMD is less common but more devastating. It can cause more progressive loss of vision with the formation of a choroidal neovascular membrane (CNV), exudation and eventually disciform scar formation.
Can AMD be prevented?
Currently there is nothing known to prevent AMD. Many associations are working very hard to find ways to treat and even prevent this blinding condition. It is therefore very important for any person over the age of 60 years, or with a family history of AMD, to have regular eye examinations by an eye care professional, in order to diagnose and treat this condition in the early stages. Special instruments can be used in order detect AMD, and different treatment options can then be discussed with the eye care professional.
What are the risk factors associated with AMD?
Except for the most common risk factor, Age, the following factors have been linked to patients with AMD, and includes genetic factors, smoking, family history of AMD and UV / blue light, with men and woman being affected equally.
How can AMD be diagnosed?
During regular eye examinations by your eye care professional, the following diagnostic tools can be used in order to make the diagnosis of AMD:
Visual acuity testing using a standard eye chart
Amsler grid testing to detect the extent of sight loss spots. This test can also be used by the patient for home testing to detect any changes between eye examinations.
Colour testing and dark adaptation testing using special charts
Fundus fluorescein angiography in which a special dye is injected into the arm vein, in order to take pictures of the back of the eye through special lens filters, to detect the formation of new / leaking blood vessels and the formation of a choroidal neovascular membrane.
Ocular Coherence Tomography (OCT) which can give the eye care professional a three dimensional visualization of the retina, in order to detect any change in the structure and the thickness of the macula, and the formation of drusen.
Is there any treatment for AMD?
Currently no effective treatment exist for Dry AMD. Some trials have indicated the benefits of taking special supplementation to decrease the progression of Dry AMD, and patients are encouraged to ask the eye care professional about these supplementations. A healthy lifestyle, the cessation of smoking and regular eye examinations is higly recommended.
A number of treatment options exist for Wet AMD and may include the injection of anti-angiogenic drugs into the eye to prevent the formation of new abnormal blood vessels. Photodynamic therapy may also be of benefit in some cases of Wet AMD, but mostly these treatment options are not of any benefit in retinas that have suffered years of damage, so early detection remains important.
Please feel free to contact your eye care professional to make an appointment if you or a family member are worried about Age related Macular Degeneration(AMD).