Introduction Macular degeneration causes loss of vision in patients over the age of 60 in most instances. Although most people have heard about the distinction between dry (the good type) and wet (the bad type) these are in fact different manifestations of the same disease and patients develop the wet version on the background of dry macular degeneration. Unfortunately, the dry type can also seriously disrupt vision as it causes the loss and disorganization of the light sensitive tissues so important for reading and looking at fine detail. The aim of treatment of wet macular degeneration is to stop the growth of new blood vessels under the retina and convert the condition to the dry type.
Description Macular degeneration (AMD) is a degenerative disease of the macula which becomes more common with age. The macula is the centre of the retina, a tissue which can be compared to the film or digital chip of a camera. Diseases of the macula are very likely to disturb vision and AMD is the commonest cause of visual loss in patients over 65. AMD varies in severity, with only the severe forms of the disease resulting in visual loss. Nevertheless, the disease is common and 1.6 million people in the UK 55 years or older have intermediate AMD or worse. Around 260,000 of these will over a period of 5 years would progress to advanced AMD with vision loss. Advanced AMD can be caused by thinning and atrophy of the retina (this is known as dry AMD) or by new blood vessels growing under or above the retina (wet AMD). The risk of both types may be reduced with dietary and possibly lifestyle changes, but only the wet form of the disease can currently be treated.
Symptoms The symptoms can come on quite quickly (one day to 2 weeks) and progress over 2 months to 2 years). They include:- i) blurring of vision or blind spots in the centre of our vision. This usually affects reading vision more than distance vision. Side vision is unaffected – you will still be able to get around ii) distortion – look at the edge of a door frame and check the edge is straight. If it has a kink in it, the you have distortion. iii) changes in the sizes of objects. Objects appear smaller or larger in the affected eye when compared to the other eye.
How may this affect you Reading, recognising faces and watching the television may be noticed first, following by difficulties cooking, gardening and driving. If the vision deteriorates sufficiently badly in both eyes, we might consider registering you as partially sighted and calling in help from the Kent Association for the Blind, who are excellent in helping patients cope with reduced vision.
Diagnosis Most patients are referred via their optician after noticing blurring or distortion of their vision. When seen by me, you will have your vision tested before drops are put into your eye to dilate the pupils. If required further tests such as fluorescein angiography and ocular coherence tomography will be arranged. These are useful for distinguishing between various subtypes of AMD (which may be important in discussions with the Primary Care Trust) and providing a baseline thickness measurement of the retina (which is helpful in monitoring the progress of treatment).