What is Macular Degeneration?
Age-related macular degeneration (ARMD) is the commonest cause of vision loss in people aged over 50 years old. The prevalence (number of new cases each year) increases with age. It is caused by degeneration of the macula, the central and most sensitive part of the retina at the back of the eye.
What is the Macula?
The macula is the central part of the retina which is responsible for enabling fine detail to be discerned. The remainder of the retina enables ‘peripheral vision’ only. Without the use of the macula, tasks like reading small print and recognising faces become difficult or impossible. The macula contains a yellow pigment (hence the term macula lutea).
The disease becomes increasingly more common amongst people in their 60s and 70s. By the age 75, almost 15% of people have this condition to some extent. The biggest risk factor is thus age. Other risk factors are a family history of the condition, cigarette smoking, and being white caucasian.
What are the types of ARMD?
There are two main types of ARMD often termed ‘Dry ARMD’ and ‘Wet ARMD’. The pathological process is different between the two. In the wet form, there is a proliferation of abnormal blood vessels under the macula. In dry ARMD, there is the collection of small yellow deposits within the retina called druse, and degeneration (atrophy) of the retinal tissue at the macula. The dry form is more common, but the wet form is usually more sudden and devastating to the vision.
The paler elevated area at the macula represents the area where the retina is elevated, under which there is an abnormal ‘membrane’ due to abnormal proliferation of blood vessels.
What does ARMD do to the vision?
ARMD affects only the central area of the vision. The condition thus never causes complete blindness or loss of sight.
Is there any treatment for ARMD?
Currently, there is no treatment for Dry ARMD. The risk of developing ARMD can be reduced by not smoking. Studies have given us some evidence that a diet rich in antioxidants and certain pigments (found in dark green vegetables like broccoli and kale) may reduce the risk of progression of the disease process.
Wet ARMD can be treated using an Anti-VEGF injection.
VEGF is an acronym and stands for Vascular Endothelial Growth Factor. The injections aim to reduce the proliferation of the abnormal blood vessels that grow under the retina in wet ARMD. More than one injection is often required as well as long term follow up. Currently these treatments are carried out at the Royal Victoria Infirmary in Newcastle and also at Corbridge Health Centre.
Screening for ARMD
Using the OCT screener which is incorporated in our Advanced Eye examination allows us to screen for both forms of ARMD. As Wet ARMD can be treated, it is vital that it is detected at the earliest possible opportunity. Unfortunately most people with Wet ARMD also have some degree of Dry ARMD as well which can make the diagnosis without an OCT image quite difficult.
With our OCT scanner we have been able to pick up cases of Wet ARMD at an early stage leading to prompt and effective treatment.