• Types
• Symptoms
• Treatment options

Types

People with untreated diabetes are said to be 25 times more at risk of blindness, than people without diabetes. All diabetics do not develop diabetic retinopathy. But in those that do, the problem begins with the tiny blood vessels leading to the retina.

At the back of the eye lies a light sensitive tissue called retina. When light falls on the retina, it converts the light into nerve signals and conveys it to the brain. There are tiny blood vessels ferrying nutrition to the retina. When blood glucose levels are high these capillaries could be affected.

Non proliferative retinopathy: When the small blood vessels in the retina begin to leak, the blood and fluid flow on to the macula (macula is that part of the retina that makes us see detail). Fatty deposits from this ooze (exudate) settle on the macula and make it swell. This is called retinal or macular oedema. This causes vision to blur.

This problem is fairly common in people with both Type I and Type II diabetes, though it is more common in the latter.

Proliferative retinopathy: This is a more serious condition than non proliferative retinopathy. Here the tiny blood vessels are clogged. To perform their function, new blood vessels are formed. These are formed on the surface of the retina. These blood vessels are weak and grow in the wrong place. This growth is called Neovascularisation.

Proliferative retinopathy can have the following effects:

• If these abnormal blood vessels grow around the pupil, glaucoma can result from the increasing pressure within the eye.
• These blood vessels have weak walls and can leak blood and can cloud the vitreous (the clear, jelly-like substance that fills the back of the eye) and partially block the light passing through the pupil to the retina, causing blurred and distorted images.
• This might cause scar tissue to grow that can pull the retina away from the --back of the eye. When the retina is pulled away it is called retinal detachment and if left untreated, retinal detachment can cause severe vision loss, including blindness.

Proliferative retinopathy develops more often in Type I diabetes (juvenile onset diabetes).

Pregnant women with diabetes are also at risk of diabetic retinopathy.

Symptoms

The dangerous thing about diabetic retinopathy is that the symptoms go unnoticed for sometime. If you have macular oedema you may not be able to read or drive. Your vision may get worse or better during the day.

If a small blood vessel haemorrhages (breaks and leaks) you feel there is a dark spot floating in your eye. After a while it disappears. A bigger blood vessel haemorrhages after a few days. Haemorrhages can happen even while you are asleep.

Some of the common symptoms are:

• Difficulty in reading
• Blurred vision
• Seeing Dark spots
• Seeing rings around sources of light
• Sudden loss of vision in an eye.

These are common symptoms for many eye problems. Just having any of these symptoms does not imply that you have diabetic retinopathy. But it is good to go for an eye examination if you have these symptoms.

What are the treatment options?

The important thing is to get your eyes tested before the retina is damaged irreparably. Treatment stops further damage to vision and stabilises the eye but there is no promise for regaining vision if it is already impaired. The two common treatment procedures are Laser surgery and vitrectomy.

Laser surgery: A high-energy beam of light is focused on the leaking blood vessels. It helps to seal them up. This prevents further leakage and reduces macular oedema.

In proliferative retinopathy, laser light is made to scatter over the back of the eye to shrink the new, abnormal blood vessels. This may weaken the patient’s peripheral vision a bit. Night vision and colour perception may also reduce a bit.

Vitrectomy: This is done when the blood vessel leaks have clouded the clear solution in your eye. Doctors wait to see if it clears on its own. This often happens. But when there are fairly big haemorrhages, it might be difficult. The surgeon operates to remove the clouded solution and then replaces it with clear liquid.

Post operative follow-ups are necessary to avoid recurrence. The standing rule is that the patient keeps blood sugar level down.