Diabetic Eye Disease
What exactly comprises diabetic eye disease?
Complications arising from diabetes may result in a group of eye problems collectively called as the Diabetic Eye Disease. If not treated well in time, these can even result in loss of vision or blindness.
This is perhaps the most common of all the diabetic eye disease and results in damage to the blood vessels of the retina, the light sensitive tissue at the back of the eye. At times, the blood vessels swell, leaking the fluid (macular oedema) or new blood vessels grow on the surface of retina. It usually affects both eyes and may lead to vision loss over a period of time. Chronic diabetes causes damage to the eye’s retina.
Cataract involves clouding of the lens of the eye and develops at a relatively early stage of diabetes.
Glaucoma pertains to optic nerve damage due to an increase in the fluid pressure inside the eye. If untreated, it leads to loss of vision.
Scarring in diabetic retinopathy causes a part of the retina to pull away from the back of eyeball.
Stages of diabetic retinopathy
Mild Non-proliferative Retinopathy
Microaneurysms, small balloon-like swellings in tiny blood vessels of retina are characteristic of this stage.
Moderate Nonproliferative Retinopathy
As the diabetes advances in the patient certain blood vessels nourishing the retina get blocked.
Severe Nonproliferative Retinopathy:
More and more number of blood vessels start getting blocked and as a result many areas of the retina are unable to get blood
supply. This sends signals to grow more number of blood vessels.Proliferative
Proliferative Retinopathy: This is the final stage which witnesses the growth of new blood vessels along the retina and the surface of the clear vitreous gel in the eye. Since these blood vessels have thin, fragile walls, a leakage of blood into the eye from the same can result in severe to complete loss of vision.
At times, the fluid from these blood vessels can leak into the centre of the macula, part of the eye responsible for sharp, straight-ahead vision. This results in a condition called macular oedema wherein the macula swells while blurring the vision. Advanced Stage IV of proliferative retinopathy and macular oedema (can occur at any stage of diabetes) can develop without symptoms or pain. At
times, the patient might be able to see fine but will still be at a high risk of loss of sight.
- Duration of diabetes: The longer you have had diabetes, the higher your risk of developing retinopathy. It is uncommon if you have had diabetes for less than five years. However, around 9 in 10 people who have had diabetes for longer than 30 years can be affected.
- Poor glucose control: Studies have shown that those people with poor control of their diabetes are more likely to develop complications, including retinopathy.
- High blood pressure: If your blood pressure is not well-controlled then this will increase your risk of developing retinopathy.
- Nephropathy (kidney disease): Having kidney disease as a result of your diabetes is associated with worsening retinopathy.
- Pregnancy: Being pregnant may make retinopathy worsen, especially if your blood glucose is poorly controlled.
- Other risk factors include smoking, obesity and a high cholesterol level.
What can be done?
The key is to keep your diabetes and blood sugar levels under control. It is very important for diabetics to control their blood pressure and cholesterol levels in addition to quitting smoking as everything will ultimately snowball into diabetic eye disease. Avoid resistance or high-impact exercises, since the same can strain the already weakened blood vessels in the eyes resulting in the leakage.
The non-proliferative stages of diabetic retinopathy do not require any treatment unless there is a macular oedema. For others, the treatments are as follows:
Scatter Laser treatment or Panretinal
Photocoagulation Used in proliferative retinopathy, the treatment aids in downsizing or shrinking the abnormal fragile blood vessels in a large area of your retina, which have not started bleeding yet. More than on session is required for the completion of the treatment due to high risk of new bleeding. Though there will be some loss of side vision, the scatter laser treatment will save the rest of your sight. The side effects include a reduced color and night vision. The treatment can be carried out despite the occurrence of limited bleeding.
If the bleeding or hemorrhage from blood vessels in the vitreous gel of the eye is severe, vitrectomy has to be performed for removing the blood from the centre of eye. Vitrectomy in both eyes is carried out separately at a difference of several weeks. Vitrectomy may also be used to correct and repair retinal detachment.The procedure can be performed under both local or general anesthesia while the vitreous gel clouded with blood is taken out after a tiny incision in the eye. The vitreous gel is then replaced with a salt solution since the consistency of vitreous gel is mostly water. The doctor will advise eyedrops to rule out any infection and an eye patch to cover your eye in the initial period.
Focal Laser Photocoagulation Surgery
Macular edema is treated with more than one session of focal laser surgery aimed at controlling the leakage of fluid in retina. The surgery is carried out only in one eye at a time, and in case the other eye is also affected, the focal laser surgery would be conducted several weeks apart. This treatment results in stabilizing and even improving the vision. Experts are of the opinion that the focal laser treatment decreases the risk of sight loss by 50 percent.
An early diagnosis of diabetic retinopathy is the only way to prevent loss of vision since the laser surgery usually cannot restore the lost vision. Refer to a specialist in low vision in case you have lost sight from diabetic retinopathy. Research is being focused on drugs which prevent growth of abnormal blood vessels and corticosteroids that can be injected into the eyeball for achieving the results.
- People with diabetic retinopathy, quite often, do not have any symptoms until major bleeding or severe damage to the eyes happens. This necessitates regular eye examination.
- Symptoms of diabetic retinopathy include:
- Floaters in the eye
- Blurring of vision and inability to focus due to haziness
- Shadows or areas missing from the picture or you have blind spots
- Progressive though slow loss of vision
- Trouble seeing at night or in dim light.
- Double vision (two images of the samething)
- Pain in one eye or headache
Eye examination for diabetic retinopathy is required in following cases:
- Adults diagnosed with Type 2 diabetes immediately require an eye exam
- Within 5 years of diagnosis of Type 1 diabetes in case of adults
- Children above 10 years of age diagnosed with diabetes for 3 – 5 years or more
Why is it important to detect diabetic retinopathy early?
- Diabetic Retinopathy (DR) is a microvascular complication of diabetes due to disorder of retinal circulation that compromises the delivery of oxygen and nutrients to meet the high metabolic demands of the retina.
- Diabetic retinopathy, the main cause of visual loss in diabetic people is the leading cause of preventable blindness accounting for 24 per cent of blindness.
- DR is usually asymptomatic in the earlier stages when it is amenable to treatment. In the late symptomatic stage it is difficult to restore the visual loss completely though further progression can be reduced.
- Detection of diabetic retinopathy signals vascular involvement and such patients are likely to have diabetic nephropathy especially in T1DM and increased risk of coronary artery disease in T2DM.
- Patients with proliferative diabetic retinopathy should avoid strenuous activities and aerobics that increase intraocular pressure. They should avoid head down activities and jumping.
Macular edema is any retinal thickening within two disc diameters of the centre of the fovea or involving it. Macular edema
commonly occurs in T2DM and is the most common cause of visual loss in DR. and laser therapy should be considered.
Macular edema can occur with or without clinical signs that define DR. It is usually invisible on direct fundoscopy but can be clinically detected using slit-lamp biomicroscopy. FFA and OCT are the other methods of diagnosing macular edema.