Diabetic retinopathy

What is Diabetic retinopathy?

Retina is the thin film of tissue at the back of your eye. This tissue is responsible for our vision. Due to long duration of diabetes and/or uncontrolled blood sugar, some changes happen in the retina and those changes are collectively called "Diabetic retinopathy".

There can be spots of bleeding or swelling in the retina. Later, small fragile blood vessels grow from the retina. These growing vessels are very delicate and bleed easily. The diseased retina releases special growth chemicals (eg. VEGF). These chemicals increase bleeding and swelling in the retina.

What are the treatment options for Diabetic retinopathy?

After your retina specialist does a complete retina examination which might include eye scanning, the most suitable treatment option for your eye condition can be suggested. In few patients who are in the earliest stages of the disease, the retina specialist may not advise any immediate treatment. Good sugar and BP control is essential. If treatment for Diabetic retinopathy is required, one or more of the following options may be recommended.

LASER: Retina laser treatment works best before new small blood vessels start to bleed. It will stop the growth of new vessels, shrink them and prevent bleeding. After 4 to 8 months, these new vessels may again start growing and require laser multiple times. Hence, regular follow up is needed. It is also important that along with laser treatment your blood sugar, blood pressure and cholesterol should be under strict control.

The laser is done in the out-patient department. No admission is needed. Pupil is dilated with the drops. Anaesthetic eye drops are put in the eye. A specialized lens is used to focus the laser on to the retina. Usually it is done in multiple sessions as advised by your doctor.

Limitations: LASER treatment should be started as soon as possible. Benefit of laser decreases if treatment is started late. Patients with aggressive and advanced disease may require more laser sessions. Laser preserves central vision but may cause loss of peripheral vision, night vision and color vision. In few patients, laser may be insufficient to stop the progression of diabetic retinopathy and decrease in vision can occur.

ANTI-VEGF INJECTIONS: At times, injections of special drugs have to be given inside the eye to reduce the growth of small blood vessels and to decrease the swelling in the retina. It may be required to repeat the injection after seeing the response to last injection.

Limitations: Patient with aggressive and advanced disease may need multiple injections. There are minimal chances of getting infection and retinal detachment following the injection.

VITRECTOMY: Vitreous gel in the center of the eye is removed through micro-openings using vacuum driven instrument called the vitrector. This procedure is to treat severe bleeding into the vitreous gel and also to remove the pull on the retina (tractional retinal detachment). After completion of surgery fluid, gas or oil may be instilled inside the eye. If oil is put then one more surgery is needed to remove the oil. Vitrectomy is the last option in treating PDR and visual results are generally limited.

What should everyone with Diabetes know about Diabetic retinopathy?

Diabetic retinopathy is the most common microvascular complication of diabetes and EVERY DIABETIC patient is at risk for developing retinopathy. It is best to see an eye doctor when VISION IS NORMAL. This helps to detect retinopathy in early stages when damage to retina is minimal and save good vision.

Most patients visit their eye doctor only when vision decreases. This means there is substantial damage to the retina already. Although few patients have improvement in vision with treatment, in a vast majority, the goal of treatment is to save existing vision and prevent further vision loss.

Without laser or anti-VEGF injections 2 to 3 out of 10 patients can lose their vision every year. There is no fixed number of laser/injections for a particular eye. Multiple sessions of laser and/or injections are necessary depending on your diabetic status and response of the eye to the previous injection/laser. If your diabetes is controlled the benefit of treatment may last for a long time.

My blood sugar is under control now. Why is my vision less?

Retinal damage is not because of “present” sugar level. It is because of long term structural changes. Controlling sugar level is essential to prevent further worsening of the disease. However, retinal damage that has already occurred cannot be reversed fully.

Will my vision become “normal” after “one” retina injection / laser / surgery?

Injection / laser / surgery in retinopathy is for bleeding, swelling and / or retinal detachment. Beyond these treatable factors, visual recovery also depends on the functional strength of the retina and this cannot be enhanced directly. Just as diabetes is an ongoing disease in the body and cannot be treated by “one-time” medication, retinopathy is also a dynamic disease that may require multiple sessions of treatment over a period of months. If your sugar is under control, the disease stabilizes over time.

I have Diabetic retinopathy. How often should I visit my retina specialist?

Diabetes is a disease that requires continuous monitoring and treatment with your diabetologist. Similarly, diabetic retinopathy also requires retinal evaluation at certain intervals. There cannot be a one stop or one treatment solution for this ongoing disease. Different stages of the disease require different follow-up intervals. Your retina specialist will help you with that decision based on a number of factors like severity of disease, response to treatment and presence of other risk factors. It is best to strictly follow the schedule suggested by your eye doctor.

Many patients are frustrated by the frequent visits to the hospital. Research has shown that, after one year of regular visits as per protocol, hospital visits are substantially reduced once the disease stablises. Missing out on treatment in early stages can lead to more permanent damage with time.

My uncle had Diabetic retinopathy. He had multiple injections and lasers. He also had retina surgery. Still he is unable to read well. Why is that?

As far as the retina is concerned, damage due to diabetes progresses continuously. The functional state of the retina and disease severity when treatment is begun is very important. In some patients where Diabetic retinopathy is detected early, fewer treatment sessions are sufficient to control the disease and existing good vision can be retained. In the majority who have significant retinal damage and decreased vision when treatment is started, multiple treatment modalities and sessions may be required to control the disease and prevent further damage to the retina.

Delicate central retinal tissue (the macula) that is responsible for fine vision like reading small letters can be damaged irreversibly by the disease. Hence, in those eyes, treatment may not restore that fine vision. However, it is important save whatever vision is existing so that the patient can continue performing his other day-to-day activities without complete dependence on another person. This is why your retina doctor advises continuous monitoring until the disease stablises.