Diabetes can affect your eye in a number of ways.
- The blood sugar levels can affect the lens in the eye which result in formation of a cataract.
- Diabetes affects the tiny blood vessels of your eye, a condition called diabetic retinopathy.
Retinal screening will keep a close check on early changes and ensure that any signs of progression to more serious stages of retinopathy are detected early. If diabetic retinopathy progresses, blood vessels in the retina can become blocked. The eye is stimulated into growing new vessels, which is nature’s way of trying to repair the damage. This is called neo-vascularization. Unfortunately these blood vessels are weak and grow in the wrong place (on the surface of the retina and into the vitreous gel). Possible consequences of neo-vascularization include:
- Vitreous haemorrhage: The main chamber of the eye is called the vitreous cavity which is normally filled with clear vitreous gel. If bleeding occurs, it can cause floaters (like dark hairs or blobs or a net curtain) and haziness.
- Tractional retinal detachment: Scar tissue can form on the surface of the retina, which can contract and cause a retinal detachment.
Proliferative diabetic retinopathy: The treatment for abnormal diabetic blood vessels is laser. The aim of the laser is to prevent further growth of new blood vessels and prevent bleeding. When new vessels are first detected your vision may be very good, because in the initial stages, new vessels have very little effect on the vision. You may feel that the laser has made your sight worse. It is important to remember that the laser treatment aims to prevent your vision from getting worse, which would happen if the condition is left untreated.
Diabetic Vitreous Haemorrhage: In some cases it is possible to wait for the blood to clear spontaneously. Laser treatment may then be performed to reduce the chance of further bleeding. Alternatively, a vitrectomy can be used to remove the vitreous (and blood). This reduces the vitreous pull on abnormal blood vessels and reduces the risk of further bleeding. It also allows retinal laser treatment to be performed, to reduce the oxygen demans of the retina, and reduces the drive for new abnormal vessels to grow. Laser treatment can affect the peripheral sight but may be considered to be a necessary consequence to protect central sight.
Diabetic Maculopathy: This means the macula (central vision) is affected by diabetes. Some people develop a type of maculopathy called diabetic macular oedema, where fluid collects in the macula. In most cases, injections of medicines into the eye can be used with the aim of preserving vision, although vision may improve in some treated eyes.
Tractional Retinal Detachment: This is the most advanced form of diabetic retinal disease. “Tractional” means there is pulling on the retinal surface, which is strong enough to separate the light-sensing retina from the back of the eye. A small area of retinal detachment far from the macula can sometimes be watched if it stops growing. Other times, it affects the central vision significantly enough to require surgical repair. Vitrectomy is combined with careful dissection of scars from the surface of the retina. Laser is performed to reduce risk of vessels recurring or to treat holes in the retina. The specific risks and benefits of the procedure will be discussed with each patient on an individualized basis.
More information about diabetic eye disease can be found in the links below.