The retina is the fine film that coats the inside of the eyeball.
It consists of special cells that convert light into electrical impulses. These electrical signals are sent to the brain where they are processed enabling us to 'see'. The central part of the retina is called the macula.This area is responsible for fine vision and colour perception.
Some common diseases that affect the retina:
1. Dry age related macular degeneration: This refers to ageing changes in the macula. The symptoms include blurred central vision that can cause problems such as recognising peoples' faces or reading print. The symptoms usually develop slowly. The peripheral vision is unaffected.
2. Wet age related macular degeneration: This refers to the development of new blood vessels under the retina along with the features of dry age related macular degeneration.The new blood vessels leak fluid into the macula and can cause distortion of the central vision.The symptoms tend to develop rapidly and the condition needs to be treated promptly.
The most effective treatment is anti-VEGF medicine that is injected into the gel at the back of the eye known as the vitreous.This shrinks the abnormal blood vessels and clears the fluid from the macula. Several injections are often needed to completely treat the condition.
3. Diabetic retinopathy: This refers to the effect of diabetes on the retina. Sugar within the blood can have a damaging effect on the fine blood vessels of the retina.This can lead to leakage of blood and fatty deposits into the retina.Vision can become blurred gradually if this leakage occurs in the macula. New fragile blood vessels can also grow on the surface of the retina which can lead to bleeding within the vitreous cavity and lead to sudden loss of vision.The main treatments for this condition include laser photocoagulation and injections of anti-VEGF medicines into the vitreous.
4. Retinal Vein Occlusion: This refers to a blockage in one of the veins of the retina. This can occur in the central retinal vein or one of its branches.This occurs suddenly and results in sudden blurring of vision. The degree of visual blur depends on the severity of the blockage and the location. High blood pressure, high cholesterol and diabetes are the main risk factors associated with developing this condition.Treatment options include laser photocoagulation, implanting a steroid pellet into the vitreous and anti-VEGF injections into the vitreous.Optical coherence tomography(OCT)technology allows us to see cross sectional images of the retina. Here there is a small mound within the macula that is formed by a collection of fluid.
5. Central Serous Retinopathy: This refers to a condition where fluid collects at the macula. It can lead to blurred central vision.It typically affects younger male patients. The cause is often unknown but can be associated with the use of steroid medication and mental stress.The condition often resolves on its own but occasionally laser treatment is applied to 'switch off' the leakage areas.
6. Myopia and its retinal manifestations: Myopia or short-sightedness is a very common condition. Myopic eyes are longer than normal eyes and therefore their retina is stretched over the eye wall. Regular retina check up for myopic patient is mandatory.