Good vision is essential for leading a normal and active life. There are many eye conditions to watch out for. With regular eye examinations and early detection, many eye conditions can be prevented or corrected. In this series, causes of vision loss and current treatment methods are discussed.
Part 2 – Age-related Macular Degeneration (AMD)
The macula is the central part of the retina containing the highest concentration of light sensitive cells (cones). These cells are involved with producing the image we need for fine detail tasks such are reading. In AMD these cells are damaged and cease to function properly. The Blue Mountain Eye Study found in Australians over 85 years of age an AMD prevalence of 18.5%. Risk factors for AMD include; being over 60 years of age, smoking and a family history of AMD.
There are two types of AMD:
- Geographic atrophy (also called dry AMD). A gradual breakdown of the light-sensitive cells in the macula and of the supporting tissue beneath the macula occurs. This usually results in a slow loss of vision.
- Neovascular AMD (also called wet AMD). In this condition abnormal blood vessels grow underneath the retina. These vessels are fragile and leaky and can lead to damage of the macula. The damage may progress rapidly.
Current Options for Prevention and Treatment:
- LUTINA lens material. Wearing spectacle lenses made from a new lens material may decrease the risk of AMD. LUTINA is a new lens material from Japanese lens manufacturer Tokai Optical. The material absorbs UV and high energy visible light (HEV) up to 420. 400-420nm are the wave lengths that both retinal lutein and lipofuscin absorb, thus by cutting these light waves out, the LUTINA lens may reduce oxidative stress and potentially reduce damage to the lutein and macular pigment caused by free radicals.
- There have been two large, five-year clinical trials looking at the effectiveness of taking supplements on the rate of progression of AMD; the Age-Related Eye Disease Study (AREDS; 2001) and a follow-up study the AREDS2 (2013). These studies have shown that taking supplements containing antioxidant vitamins and multivitamins including lutein and zeaxanthin can reduce the risk of dry AMD progressing to wet AMD. The studies gave the effective doses required and there are commercial products available manufactured to this formulation. These studies did not show any preventative benefit of taking supplements against the development of dry AMD in healthy eyes.
- Anti-VEGF injection therapy. One option to slow the progression of wet AMD is to inject drugs into the eye. Abnormally high levels of vascular endothelial growth factor (VEGF) are found in neovascular AMD. VEGF is a protein that promotes the growth of new abnormal blood vessels. Anti-VEGF injection therapy blocks this growth. The sooner wet AMD is detected and treatment begun the greater the chance of preserving and even possibly improving vision.
Coping with AMD and vision loss can be a traumatic experience. Normal everyday tasks such as reading, shopping, cooking, and writing can be challenging. Often visual aids such as hand held magnifiers may help. It may not be possible to restore vision, but low vision services (such as from Vision Australia) and support groups (such as the Macular Disease Foundation) can help people make the most of what is remaining.
This is general advice only and does not replace having regular eye examinations.
Dr Leisa Schmid PhD Optometrist
LensPro Brisbane City
Shop 106A, Level E
The Myer Centre
91 Queen Street
Brisbane Qld 4000
Tel: 07 3012 9099 Fax: 07 3012 9466