Article Contributed by  Dr. Vinay Nangia glaucoma and retina specialist  and Dr. Arshia Matin, Consultant. Suraj Eye Institute. – Nagpur.

Diabetes is a disorder where there is a failure to digest sugar in the body. As a result the blood sugar level goes up and upsets a number of functions in the body including the EYE.

Diabetes causes several eye problems. All can cause severe vision loss or even blindness. These include:

1. Glaucoma or increased pressure of the eye.
2. Cataract or opacification of lens. Phacoemulsification with foldable intraocular lens implant is indicated in these patients.
3.  Palsies of the nerves that supply the external muscles of the eye.

The retina is the sensitive innermost membrane of the eye, which is important for good vision. While the normal vessels do not leak, the vessel walls in diabetic patients develop tiny leaks. This results in a  swollen retina which cannot work properly. Blood vessels may also close down, impairing the nutrition of the retina. This is known as Diabetic Retinopathy.

Leaking of fluids and lipids onto the central part of the retina known as macula results in diabetic maculopathy. These changes can decrease vision permanently. If the diabetic process continues, there is formation of new blood vessels and development of bleeding within the cavity of the eye known as Proliferative Diabetic Retinopathy and can lead to total loss of sight if left untreated.

1. Duration of diabetes is the most  important risk factor. 27% of those who have had diabetes for 5-10years and 71-90% of those who have had diabetes for longer than 10years have Diabetic Retinopathy.
2. Poor metabolic control
3. Hypertension if poorly controlled.
4. Pregnancy is associated with rapid progression of diabetic retinopathy.
5.  Nephropathy or kidney involvement.
6. Other risk factors include smoking , obesity and high blood cholesterol.

Diagnosis of Diabetic Retinopathy:

The retina can be seen using a special microscope and high quality lens.
Fluorescein angiography, just like angiography of the heart, enables us to see the retinal vessels. Fluorescein dye is injected into the vein of the patient’s arm. The dye reaches the blood vessels in the retina, which are thereby easily visualized. This test helps the retina specialist to decide on the treatment.

Diabetic Retinopathy can be treated in 2 ways. These include – laser treatment and vitreous surgery. Both are very effective in reducing vision loss from this disease.

The Argon Laser and its beneficial effects have revolutionized treatment of Diabetic Retinopathy.
Argon Laser treatment is done, when there is swelling of the macula or when the retina is susceptible to development of new vessels.

It is done as an outpatient procedure, using topical anaesthetic drops. There is little or no discomfort, admission is not required and patients can continue with their routine life immediately after it.

Bleeding from new retinal vessels into the  cavity of eye is known as vitreous haemorrhage. If the retina can be seen clearly, those parts of the retina can be treated with laser. When it is not possible to do laser, then a procedure known as vitrectomy is done. High quality microscope and microsurgical instruments are needed for this. The eye surgeon should be specially trained in Vitreo-Retinal surgery..

Successful management of diabetic retinopathy via a combination of glucose control, laser therapy and vitrectomy represents one of the most striking achievements of modern ophthalmology. If retina examinations are initiated prior to the development of significant retinopathy, and then repeated periodically, the risk of severe visual loss is minimal.

The key to sight preservation for diabetic patients is routine examinations to detect the earliest signs of retinopathy.