Diabetes affects the eye in many ways. This section will deal with its effects on the retina. Raised blood sugars (>8) cause sorbitol to be deposited in the lining of the capillaries throughout the body. This causes slow and inefficient circulation. The retina uses large amounts of oxygen and if it doesn’t receive all that is requires, it begins to send out chemical messages that affect leakage from vessels and the growth of new blood vessels. Leaking vessels cause the macula to swell (diabetic maculopathy)and the growth of new blood vessels causes bleeding into the vitreous gel of the eye (Proliferative retinopathy). Risk factors for the development of diabetic retinopathy include the duration of diabetes, sugar control (good <8), smoking (STOP!!!), raised cholesterol. Screening should occur once a year where you visit the rooms and your pupils are dilated with eye drops. We then examine the retina and advise what followup and treatment is required.
This is the commonest cause of visual loss in diabetics. When the macula swells, your central vision is affected to varying degrees. You may also be aware of distortion of objects you are looking at. Examination and OCT are required to evaluate the condition of your eyes and plan treatment. If there is significant visual loss and or thickening of the macula, you will be offered an injection into the vitreous of your eye. This is not as scary as you think and we make every effort to make the whole experience as pleasant as possible. Please see the section on intravitreal injections. In certain situations we still perform macular laser with the Argon laser , but this is not as common as it used to be. Injections offer the best possibility of visual improvement. A variable number of injections may be required depending on how chronic the edema is, and how well you respond. Not everyone responds to first line treatment and we may discuss other options with you. Poor sugar control, raised cholesterol and smoking all affect your eye negatively.
Proliferative diabetic retinopathy
When eyes become critically short of oxygen, your eye produces chemicals that cause new blood vessels to grow. These are fragile and can bleed, causing waves of red spots in front of your vision. We would prefer to see patients prior to the onset of bleeding as we can usually laser the eyes to prevent this from occurring. Depending on severity and your visual requirements, we can either observe for a short period or advocate surgery. If the bleeding is not severe, we can either inject the eye or do laser treatment.If you are any blood thinners this needs to be discussed with us as we may need to stop some of them to make your surgery safe. The surgery is called a posterior vitrectomy and can be safely performed under local anaesthetic using minimally invasive techniques. During the surgery we can perform laser with in the eye to prevent further bleeding. Depending on convenience, you can either go home after the surgery or book a bed in the hospital overnight.