Our grateful thanks to the Macular Society for their contribution to our on-air report, and for allowing us to reproduce the information below - for further help and advice visit their website by clicking here.
The macula is part of the retina at the back of the eye. It is only about 5mm across but is responsible for all of our central vision, most of our colour vision and the fine detail of what we see.
The macula has a very high concentration of photoreceptor cells which detect light and send signals to the brain, which interprets them as images. The rest of the retina processes our peripheral (side) vision. Macular conditions cause loss of central vision.
There are many forms of macular conditions, age-related macular degeneration (AMD) is the most common while juvenile macular dystrophies are very rare. Other common macular conditions include myopic maculopathy, macular holes, diabetic macular oedema and retinal vein occlusion.
Age-related macular degeneration (AMD) usually affects people over 60, but can happen earlier. It is the most common cause of sight loss in the developed world. In the UK over 600,000 people are affected.
Dry AMD causes a gradual deterioration of the macula, usually, over many years, as the retinal cells die off and are not regenerated. The name ‘dry’ does not mean the person has dry eyes just that the condition is not ‘wet’ AMD. Around 10 to 15% of people with dry AMD go on to develop wet AMD. If you have dry AMD and notice a sudden change in your vision, it is important that you contact your optometrist, or hospital eye specialist, urgently. If you have AMD in one eye, the other eye may also be affected within a few years.
In wet AMD abnormal blood vessels grow into the macula and leak blood or fluid which leads to scarring of the macula and rapid loss of central vision. Wet AMD can develop very suddenly. It can now be treated if caught quickly. Fast referral to a hospital specialist is essential.
Symptoms Macular degeneration affects different people in different ways. You may not notice any change in your vision during the early stages, especially if you have AMD in only one eye. However, as macular cells deteriorate, your ability to see clearly will change:
AMD is painless, so if you have eye pain seek urgent medical advice.
Dystrophies Juvenile macular dystrophies are a large number of rare, inherited conditions that affect central vision, not peripheral (side) vision. They can appear in childhood, but some are not diagnosed until later in life.
Macular dystrophies are caused by inheriting a faulty gene from one or both parents. Genes act in pairs and we inherit one gene of each pair from each parent. Some conditions are caused by one faulty gene from one parent, this is known as a dominant form. In these cases the parent with the faulty gene will have the condition and has a 50% chance of passing it on. Recessive forms are where parents probably won’t have the condition themselves but they both carry the faulty gene.
Some families can benefit from genetic counselling, which helps people understand their condition and future implications. Counselling can also help a newly diagnosed person tell their family about their condition, which they often find difficult. Families or individuals can be referred for counselling by their ophthalmologist or GP.
Other macular conditions
Myopic maculopathy In a myopic, or short-sighted eye, the eyeball is not spherical but instead is too long, tending towards the shape of an egg. This means light rays entering the eye are unable to focus on the light-sensitive part of the eye called the retina. In high myopia, the excessive elongation of the eyeball leads to degeneration of the retina, in particular, to the macula which has the highest concentration of light sensitive cells that interpret colour images.
Macular holes are small and develop at the centre of the macula. Symptoms for macular holes are similar to that of age-related macular degeneration. In the early stage of a macular hole, people may notice a slight distortion or blurriness in their straight-ahead vision. Straight lines or objects can begin to look bent or wavy. Reading and performing other routine tasks with the affected eye become difficult. Although some macular holes can seal themselves and do not require any treatment, surgery is necessary in many cases to help improve vision.
Diabetic macular oedema (DMO) is the most common cause of loss of vision in diabetics. Oedema is fluid under the macula caused by leaky blood vessels. DMO is a complication of diabetic retinopathy and results in a condition very similar to wet AMD. Download Diabetic Macular Oedema for further information about this condition.
Retinal vein occlusion (RVO) is one of the most common causes of sudden painless unilateral loss of vision. Although it can occur at almost any age, it typically affects older people. The condition means one of the veins draining blood out of the eye becomes blocked, causing blood and other fluids to leak into the retina, which causes bruising and swelling as well as lack of oxygen. This interferes with the light receptor cells and reduces vision.
All material on this website is provided for your information only and may not be construed as medical advice or instruction. No action or inaction should be taken based solely on the contents of this information; instead, readers should consult appropriate health professionals on any matter relating to their health and well-being.
