Macular degeneration affects the macula at the back of the eye and impairs central vision. The macular is a small area on the retina where detailed central vision takes place eg reading. The cells in the macula deteriorate and the central part of vision becomes blurred but what is seen around the blurred area is relatively clear because the peripheral area of the retina is not affected.
Who is affected?
Macular degeneration accounts for about 50% of all visual impairment in the developed countries. It usually affects people over 50years and so is known as Age-related macular degeneration [AMD].
There are other forms of macular disease which can affect younger people:
- Macular dystrophy is damage to the macula – it is rare and tends to run in families.
- Macular disease caused by diabetes ie diabetic retinopathy.
Two types of macular degeneration
Dry – Develops very slowly over a number of years with gradual fading of central vision.
Wet – Develops more rapidly.
Symptoms of macular degeneration
- Central vision is reduced and fine detail is difficult to see.
- Straight lines can appear wavy or misshapen.
- Judging distances and heights can be difficult.
- Colour perception may be affected.
If your optician, or GP suspects that you have AMD, then you will be referred to the hospital where you will have one or more of the following checks:
- Look at a grid test page to check for blind spots.
- A colour vision test.
- Photographs of the back of the eye [this means the doctor has an accurate record for future comparisons.
- Fluorescein angiogram may be used. Your pupils are dilated and a small amount of fluorescein dye is injected into a vein your arm. It circulates through the body and so the network of blood vessels at the back of the eye can be seen and if there are any leaks of the dye, then it shows the vessels are damaged or new vessels have developed. This occasionally causes nausea and the skin yellows for 3-6 hours and the urine for up to 24hours.
So far there is no treatment for the dry type of macular degeneration. Laser treatment may occasionally halt the progress of the wet type if you are seen at the early stages of development. New drugs are now also available for the treatment of wet macular degeneration.
There have been reports that nutritional supplements may help to treat AMD but they cannot cure or restore vision. The February 2006 edition of the Drugs and Therapeutics Bulletin [DTB], an independent journal providing independent evaluations of treatments, expressed concerns that promotion of certain nutritional supplements claiming to improve or slow down macular degeneration may be medicinal and are aimed at people who are worried about macular degeneration.
In particular DTB has reported the claim that ‘Viteyes’ can ‘slow macular degeneration’. DTB says that there is some evidence to support the use of a specific combination of antioxidant vitamins and zinc, the so-called AREDS formula, in specific groups of patients with macular degeneration – those with advanced disease in one eye only but this formula can only be found in a few products – ‘VisiVite Original Formula’, ‘Viteyes AREDS Formula’ and ‘Ocuvite PreserVision’. The use of other nutritional supplements, or use in other groups of people, cannot be recommended.
Warning note: manufacturers based outside the UK can continue to make inappropriate claims for their supplements because they fall outside UK jurisdiction.
DTB’s advice to people with macular degeneration includes stopping smoking and eating a healthy diet rich in green vegetables.