DIABETIC RETINOPATHY

DIABETIC RETINOPATHY

Diabetes mellitus is a disease wherein body is unable to use and store sugar leading to increase in blood sugar level. It damages many systems in body including eye. Common complications are cataract, glaucoma and retinopathy. With improved treatment of Diabetic patients and increased longevity, Diabetic Retinopathy has become major cause of blindness all over the world.

What is retinopathy?

NPDR with maculopathy

Diabetes causes the damage of retinal blood vessels, leading to leakage of fluid and blood. There may be new development of blood vessels, which are fragile. This is known as neovascularisation. (.....More.....)

There are two forms of retinopathy :

Non Proliferative Retinopathy (NPDR)
Proliferative Retinopathy (PDR)

Non Proliferative Retinopathy (NPDR)

This is early stage of retinopathy. In this, blood vessels decrease in size, enlarge like a balloon sac (Microaneurysm). There may be leakage of fluid, forming deposits (exudates) and bleeding (Retinal haemorrhage).

In 80% of cases it remains like this and does not effect vision. But in some cases above changes involves macula (diabetic maculopathy) leading to loss of vision and may progress to more advanced stage such as Proliferative Retinopathy.

Proliferative Retinopathy (PDR)

Here in addition to changes of NPDR there is also formation of new vessels which are too fragile, bleeding easily to cause Vitreous hemorrhage. The blood in the vitreous leads to blurred vision and sometimes even to loss of vision.

In addition to this, scar tissue may form from ruptured blood vessels, which may pull on the retina leading to retinal detachment (Traction retinal detachment).

In more severe cases blood vessels may grow on the Iris (Rubeosis). These blood vessels may close off the normal flow of fluid out of the eye and lead to raised pressure in the eye - secondary glaucoma (Neovascular type). This may lead to painful blind eye.

If all these are not managed properly in early stage they might lead to blindness.

FFA of PDR Case	PDR with Scar tissue	PDR with bleeding

Risk factors for diabetic retinopathy

The risk of developing diabetic retinopathy is more with:

	Increase duration of diabetes.
	Poor control of diabetes.
	Hypertension (high blood pressure).
	Kidney diseases.
	Pregnancy.
	Hereditary
	After cataract surgery

Diagnosis

Diabetic retinopathy is normally asymptomatic until it causes visual loss by macular involvement or vitreous hemorrhage or retinal detachment. Annual eye check of diabetic patients is a must. In pregnancy retina should be checked in first trimester and should be followed up closely. The doctor examines the retina by ophthalmoscope. It is a painless procedure.

Once the disease is diagnosed further information may be gained by Fundus Fluorescin Angiography. In this procedure fluorescin dye is injected in vein in hand and retinal photographs are taken. This gives the details of blood vessels, leakage from them and about new vessels.

Treatment

	Medical treatment:	There are no medicines to prevent or reduce retinopathy. However, good control of diabetes may delay the development of disease and its severity.
Laser:		Laser is main way of treatment. A powerful beam of laser (light energy) is focused on the retina, which forms tiny scars on the retina. This reduces leakage in cases of background retinopathy and new vessel growth in proliferative retinopathy. The treatment is painless, does not involve any cutting or injection and is performed in the doctor’s clinic. It prevents further deterioration of vision but one should not expect to restore lost vision by this treatment. Laser cannot make blood disappear but prevents further bleeding. In cases of proliferative retinopathy laser is done throughout the peripheral retina. It may cause reduced side vision and reduced vision in dim light. The effect of treatment may not be apparent for months and may need regular check ups.
Vitrectomy:		Laser may not be possible in more advanced cases of diabetic retinopathy having vitreous hemorrhage. These cases need vitrectomy to remove the blood and scar tissue. Laser treatment is done in same sitting to prevent further bleeding. Retinal detachment also needs vitrectomy. Retinal detachment needs urgent vitrectomy. It is also indicated in cases of: Diffuse macular oedema not responding to laser therapy, Iris neovascularisation Hemolytic glaucoma Dense premacular haemorrhage Premacular fibrosis
Intraocular Steroids:		Intraocular Triamcinolone Acetonide is used in cases of Diabetic maculopathy not responding to laser treatment. It is an minor procedure. Risks are: 1) Sudden loss of vision by deposit of drug on macula. 2) Retinal detachment and Endophthalmitis. 3) Secondry Glaucoma.