Looking at macular degeneration
Posted on 2 June 2017
The leading cause of vision loss, macular degeneration primarily affects people over the age of 50. While it can be treated, there’s no known cure. Here’s what you need to know.
According to the American Macular Degeneration Foundation, the condition causes more vision loss than cataracts and glaucoma combined. Yet it doesn’t cause complete blindness, but rather the loss of central vision says Dr Shaun Thompson, an ophthalmologist based at Mediclinic Tzaneen and Mediclinic Limpopo.
Types of macular degeneration
‘The macula is the area of your eye that is most sensitive for seeing detail – the centre of your prime vision,’ explains Dr Thompson. ‘Macular degeneration happens mostly with older people from their 60s into their 70s, 80s and 90s – the older you are, the higher the risk.’ While forms of macular degeneration can strike younger people, especially those with a genetic predisposition, this is quite rare, while age-related macular degeneration is very common.
There are two types of age-related macular degeneration (AMD):
- Dry AMD: The first sign is seeing little white dots at the back of the eye. ‘It’s probably not doing any damage yet at that stage. The rods and cones – the two types of photoreceptors in the human retina – start dying off and then you get little gaps in your vision in that sensitive area which is called dry AMD (age-related macular degeneration),’ explains Dr Thompson.
- Wet AMD: When it worsens, you get little cracks in the back of the eye and abnormal blood vessels grow through the macula and retina, causing wet AMD. ‘If it’s wet, we can keep it under control and keep the vision going for a long time but generally the little gaps eventually become big gaps – much like a big hole in the middle of your vision,’ explains Dr Thompson. ‘However, you can still see around that gap.’
Signs of wet AMD
If wet AMD is caught early it’s easier to treat. ‘If we see someone with dry macular degeneration – that’s how it normally starts – we warn them to test their vision on a regular basis, testing each eye independently,’ says Dr Thompson. ‘If they look at a straight line, such as a door frame, and it looks like it’s bending, or if there’s a really quick degeneration in vision over a few days or weeks, then the patient’s eyes must be checked quickly to see whether it’s converted to wet AMD.’
‘Regular comprehensive eye exams can detect macular degeneration before the disease causes vision loss,’ reports the National Eye Institute in the US. ‘Treatment can slow vision loss. It does not restore vision.’
According to Dr Thompson, wet AMD is treated with an injection of anti-angiogenic medications into the eye, which stops the growth of excessive blood vessels. Commonly used drugs include Avastin and Lucentis, which keep the disease under control.
According to Dr Thompson, a multivitamin called Ocuvite is used in the treatment of dry AMD. It was shown in the National Institute of Health (NIH) AREDS studies to be most effective in slowing down the dry type of AMD.
‘Smoking and poor eating are huge dangers for macular degeneration patients,’ says Dr Thompson. Lifestyle factors that help to offset or slow down the progression of macular degeneration therefore include stopping smoking, eating a healthy diet high in green leafy vegetables and fish, and exercising.
Impact on vision
‘The loss of central vision in AMD can interfere with simple everyday activities, such as the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house,’ reports NIH Senior Health.
‘Macular degeneration never leads to complete blindness,’ emphasises Dr Thompson. It rather results in the loss of central vision. ‘Generally people can’t read at all or they need to use a magnifying glass to read with. However, they can move around freely and will never have to walk with a stick.’