Age related macular degeneration (AMD)
AMD is a disease of the macula which is responsible for our sharpest central vision. It tends to affect people over the age of 55 and it starts out with a gradual deterioration in central vision which is not correctable with spectacles.
There are 2 types of AMD; dry and wet. The commoner dry type affects vision very gradually (usually over years) whereas the wet type can cause rapid deterioration in central vision in the form of distortion or a central dark patch (scotoma). The dry type can switch to the wet type at any time.
There is currently no curative treatment for the dry type of AMD although plenty of research is looking for potential therapies which may become possible in the future.
Wet AMD is caused by abnormal blood vessels that grow under the macula which leak fluid or blood that can cause damage and scarring to the sensitive structures in the macula. We now have treatment that can dry up the fluid and blood and protect the macula from scarring which reduces vision. The medication has to be delivered through the white of the eye into the vitreous cavity which sits in front of the retina. This has been shown in numerous clinical trials to be the most effective treatment for wet AMD. The drug gets absorbed over a few weeks and therefore the injections have to be repeated, initially on a monthly basis which can then be extended depending on the response.
Diabetes can affect the retina and the macula over time. Every patient with diabetes needs to have a thorough retinal examination with pupil dilation at least once a year in order to detect any changes before they start to affect vision and cause permanent damage.
High blood sugar levels over time make blood vessels leak fluid into the macula which reduces central vision. This is referred to as Diabetic macular oedema (DMO). DMO, if left untreated, can cause irreversible damage to central vision. Treatment of DMO depends on the location and extent of fluid in the macula. In very mild cases, simply controlling blood sugar levels and blood pressure can reverse the oedema. More advanced cases of DMO would need treatment with either Laser or intravitreal injections.
Diabetes can also lead to retinopathy. This starts out with mild changes to retinal blood vessels but can advance with time and uncontrolled blood sugar levels to the more vision threatening form of proliferative diabetic retinopathy. In proliferative diabetic retinopathy, abnormal blood vessels start to grow in the retina which can cause bleeding and, if left untreated, can lead to retinal detachment. Proliferative diabetic retinopathy is treated with laser to the retina and in some cases intravitreal injections need to be given in addition to laser.