Diabetic Retinopathy

What is Diabetic Retinopathy?

Diabetic retinopathy, also known as diabetic eye disease, is a complication of diabetes (both type 1 and type 2). Persistently high blood sugar levels damage the blood vessels of the retina and, if left untreated, can cause blindness. How long you have had diabetes, and how well it is controlled, are both important factors in the progression of this eye disease. Fortunately, much can be done to monitor, slow and treat diabetic retinopathy. Keeping blood sugar, blood pressure and cholesterol in check is very important, as is working with an eye specialist experienced in diabetic retinopathy, who can evaluate your eyes regularly and provide appropriate treatment.

Before treatment of diabetic retinopathy

Floating spots appear in the vision, and abnormal retinal blood vessels may bleed.

After treatment of diabetic retinopathy

The floating spots are gone, the bleeding has stopped and vision is clear again.

How do I know if I need the help of a diabetes eye specialist?

Quite simply, if you have diabetes — or are at risk of it (often called prediabetes) — you should be under the care of an ophthalmologist who specialises in diabetic eye disease. Good management of the condition is key to preserving the best possible vision throughout your life, and only regular check-ups with an ophthalmologist experienced in monitoring and treating diabetic retinopathy make early intervention possible should complications arise. While anyone with diabetes is at risk of developing diabetic retinopathy, certain additional factors increase the likelihood or speed of its progression. These are:

• Smoking
• Hypertension (high blood pressure)
• High cholesterol
• Poorly controlled blood sugar
• Certain ethnicities – Hispanics, Native Americans and African Americans
• Pregnancy

In addition, the longer you have had diabetes, the greater your chance of developing diabetic retinopathy. The complications of diabetic eye disease are many, and ophthalmologists specialising in diabetes are highly trained to spot the early signs during routine eye examinations. The retina is the light-sensitive layer of cells at the back of the eye that converts light into electrical signals and transmits them along the optic nerve to the brain. To work effectively, the retina needs a steady supply of oxygen-rich blood, delivered through a network of tiny blood vessels. When blood sugar remains uncontrolled for long periods, this network weakens and breaks down. Left untreated, in severe cases this can lead to permanent loss of vision.

There are two stages of diabetic eye disease – early diabetic retinopathy and advanced diabetic retinopathy. In the early stage you are unlikely to notice any obvious symptoms, but the anatomical changes taking place within the eye will be picked up during a routine diabetic eye examination by your ophthalmologist. If you experience any of the following symptoms, see your eye doctor immediately:

• Floaters (shapes that drift across your field of vision)
• Blurred vision
• Eye pain
• Redness
• Any worsening of your vision
• Sudden loss of vision

Treatments used to treat the worsening of diabetic retinopathy include:

Laser treatment

There are several types of laser treatment. The first, called photocoagulation or focal laser therapy, stops or reduces leakage from blood vessels by sealing them with a laser burn. The second, panretinal photocoagulation or scatter laser therapy, uses the laser to shrink abnormal blood vessels and so prevent them from leaking; this treatment is carried out over multiple sessions. Laser treatments are generally performed under local anaesthesia and take about 30-40 minutes per session.

Eye injections

These are used to treat severe diabetic macular oedema, a condition in which the central part of the retina (the macula) swells. The injections, known as VEGF (vascular endothelial growth factor) inhibitors or anti-VEGF, help prevent the development of new, abnormal blood vessels and swelling in the retina.

Treatment is quick and usually painless. Initially it is given once a month until vision stabilises; after that, the injections may become less frequent or stop altogether. In some cases, if anti-VEGF therapy does not work, steroid medication may be injected instead.

Surgery on the eye

Known as vitreoretinal surgery, this is performed when a large amount of blood has leaked into the eye, or when extensive scar tissue has caused — or is likely to cause — retinal detachment. It involves making a small incision and removing part of the vitreous from the eye. The operation is carried out under local anaesthesia with sedation, so it is painless and you will be unaware of it taking place.