AGE-RELATED MACULAR DEGENERATION
Age-related macular degeneration — also called macular degeneration, AMD or ARMD — is the deterioration of the macula, which is a small area in the centre of the retina of the eye that is responsible for central and colour vision.
The retina is the light-sensitive tissue located in the back of the eye. It is like the film in a camera, recording the images we see and sending them to the brain via the optic nerve. The retina almost instantly converts light images into electrical impulses through a chemical reaction. It then sends these impulses to the brain, where we interpret what we see, process the visual information, and relate what we perceive to the rest of our environment. The macula is a small portion of the retina located in the central part of the retina. The macula is responsible for central vision (straight-ahead vision) and provides the ability to see fine detail in your direct line of sight. We use the macula of each eye to have a clear view that allows us to read, drive a car, and recognise faces or colours. The non-macular areas of the retina provide us with our side and night vision.
While there are many causes of macular degeneration, and age-related macular degeneration (AMD or ARMD) is by far the most common type. AMD is a disease associated with ageing, that gradually destroys the sharp central vision that is needed for seeing objects clearly and for everyday tasks such as reading and driving. In some cases, AMD advances so slowly that people notice little change in their vision. In others, the disease progresses faster and may lead to a loss of vision in one or both eyes.
AMD occurs in two forms. “Wet” age-related macular degeneration is less common but more aggressive in its progression to severe central vision loss. “Dry” age-related macular degeneration is the more common type and is more slowly progressive in causing visual impairment.
Wet AMD occurs when abnormal blood vessels grow under and into the macular portion of the retina. These new blood vessels (known as choroidal neovascularisation or CNV) tend to be very fragile and often leak blood and fluid. The blood and fluid raise the macula from its usual place at the back of the eye and cause the central vision to blur. Under these circumstances, vision loss may be rapid and severe. Some patients, however, do not notice visual changes despite the onset of CNV, so regular eye examinations are essential for patients at risk for CNV.
Once CNV has developed in one eye, whether there is a visual loss or not, the other eye is at high risk for the same change.
In dry AMD, the light-sensitive cells in the macula slowly break down. With less of the macula functioning, central vision diminishes.
Dry AMD has three stages (early, intermediate, or advanced), all of which may occur in one or both eyes. We define these by the amount and characteristics of the drusen that are present.
Retinal drusen are yellow deposits under the retina. Dr Boitumelo Khantsi can detect drusen during a comprehensive dilated eye exam.
In addition to drusen, people with advanced dry AMD have a breakdown of light-sensitive cells and supporting tissue in the central retinal area. This breakdown can cause a blurred spot in the centre of your vision. Over time, the blurred spot may get bigger and darker, taking more of your central vision. You may have difficulty reading or recognising faces until they are very close to you.
Age-Related Macular Degeneration is a severe condition that requires consistent monitoring. If you suspect AMD, please contact Dr Boitumelo Khantsi at his Midrand or Pretoria office to schedule a comprehensive eye examination to assess the degree of degeneration and help you prevent further vision loss.