Diabetic Eye Disease
What is Diabetes?
Diabetes is a condition that affects the use of sugar (glucose) by the cells of the body. This causes high levels of sugar to circulate in the blood stream, which eventually causes damage to the small blood vessels in the body. The parts of the body most commonly affected by this process are the eye (retina), kidneys, heart, feet and brain.
When diabetes affects the eyes it is called Diabetic Retinopathy.
Diabetes is a leading cause of blindness in people of working age (30 – 60 age group). If you are diabetic it is essential that you have your eyes checked by an Ophthalmologist every year, and possibly more frequently, if your diabetes is affecting your eyes. It is also very important that your blood sugar levels, blood pressure, cholesterol and body weight are well controlled as these factors can all affect the health of your eyes.
The American Academy of Ophthalmology has strict guidelines regarding the treatment of diabetic retinopathy in order to try and prevent the complications of diabetes within the eye.
What is Diabetic Retinopathy?
Diabetes causes damage to the retinal blood vessels at the back of the eye. These blood vessels then become weakened and fluid, protein and blood can leak out of them and accumulate within the layers of the retina. If this involves the macula area (central part of the retina where best vision takes place) this is called Macular Edema and the central part of the vision may become blurred.
When the blood vessels at the back of the eye become damaged, the blood supply to the eye can also be affected leading to the formation of abnormal blood vessels within the eye. This is called Proliferative Diabetic Retinopathy. These abnormal blood vessels are fragile and can easily bleed into the eye causing a sudden reduction in vision (Vitreous Haemorrhage)
Both Diabetic Macular Edema and Proliferative Diabetic Retinopathy require prompt treatment to try and prevent permanent loss of vision. Treatment usually consists of laser. Occasionally, special injections into the eye (intravitreal injections) may be required to treat the macular edema or the proliferation of abnormal blood vessels. If there is bleeding inside the eye, laser therapy may be difficult or sometimes impossible to carry out. In this case, vitrectomy surgery may be the only way to restore vision.
LASER treatment for diabetic retinopathy
Laser is applied to the retina in 2 different ways:
- If you have Macular Edema, Laser is applied to the areas of retina that are “leaking” (Focal or Grid Argon Laser). This process is relatively quick and completely painless. Your vision will be blurred after the treatment for a few yours because of the drops used to dilate your pupils.
- If you have new blood vessels growing within the eye (Proliferative Diabetic Retinopathy), LASER is applied to the peripheral retina in a process called PanRetinal Photocoagulation or PRP for short. This treatment causes the abnormal blood vessels to shrink away. This form of Laser takes a little longer to apply and may be slightly uncomfortable. We therefore recommend taking a pain killer before this sort of treatment. You may need 2 or more sessions of PRP to get rid of the abnormal blood vessels.
Intravitreal injections (Avastin) for diabetic retinopathy
Avastin (Bevacizumab) is an antibody that binds to all forms of the natural human protein called Vascular Endothelial Growth Factor (VEGF). This VEGF stimulates the growth of and promotes leakage from blood vessels in the eye, like the ones we see in Proliferative Diabetic Retinopathy, Vascular occlusions, Age-related macular Degeneration and Neovascular glaucoma. Avastin is the first commercially available angiogenesis inhibitor, that prevents the formation of abnormal blood vessels, therefore helping in the treatment of these conditions. Although currently not approved by FDA for use in the eye, numerous studies have demonstrated that it is a safe and effective treatment for specific eye disorders.
Side effects: minimal side-effects have been reported with the use of intravitreal Avastin. Complications that relate to all intravitreal injections include: Endophthalmitis (infection in the eye), inflammation, retinal detachment, cataract and glaucoma. However, we do not recommend you have an Avastin injection if you have had a heart attack or a stroke in the last 12 months.
Vitrectomy for Diabetic Retinopathy – Vitreous Hemorrhage
Vitrectomy is the current standard technique for removal of blood within the eye. There are numerous conditions that can cause bleeding inside the eye, and by far the commonest is Proliferative Diabetic Retinopathy. The technique consists of creating 3 tiny holes on the sclera (white of the eye) through which 3 different instruments are put through. This allows for the removal of the vitreous gel and blood inside the eye. Once the blood has been removed from inside the eye, the cause of the bleeding is identified and treated. Scatter laser is then applied to the retina, causing the bleeding vessels to shrink and disappear. A bubble of air, gas or oil in then put in the eye to prevent bleeding in the immediate post-operative period. In the event that silicone oil is used, it is usually removed a few months later once the condition of the eye has stabilized. After the surgery, drops are used routinely for a few weeks to reduce the inflammation in the eye. Regular checks after the operation are required to detect and treat any complications that may arise.