Diabetic Eye Disease
Diabetes affects the retina in two ways: Diabetic Macular Edema and Diabetic Retinopathy. They are described below.
1. Diabetic Macular Edema.
The central vision, or macular area, can be affected in diabetes. Aneurysm type changes can occur in the blood vessels around the central vision. These aneurysms can leak out fluid from the blood vessels as well as protein. This leakage can affect the central vision. Our goal is to decrease leakage so that vision can be improved or at least maintained. Chronic leakage in the center vision is thought to decrease vision more so over time.
There are two methods to decrease the leakage to help improve or preserve vision. They are laser and injections with drugs that decrease leakage. These drugs are termed anti-Vascular Endothelial Growth Factor or Anti-VEGF drugs. If the aneurysms are far from the central vision they can be lasered to decrease leakage. When the leakage is too close to the center it is not safe to be lasered and so anti-VEGF drugs are injected into the eye to decrease the leakage. Sometimes even when laser is planned, anti-VEGF drugs are injected to decrease the leakage so that the laser can be better absorbed by the leaking aneurysms.
Risk of Focal (Central) Laser:
The laser is only done away from the center. This minimizes the risk to central vision. There is the risk that laser scars can expand over time and cause spots to be missing around the central vision. Again, in modern practice this is minimized as laser is away from the center and the spot sizes are small.
Risk of Anti-VEGF injections:
The main risk is a 1 in a thousand of bleeding, infection or retinal detachment. The eye can feel itchy or scratchy on the day of the injection; this usually improves by the following day. If there is persistent pain and decreased vision that does not improve, Dr. Adatia would like to see you back right away. Often this is just from a scratch or an abrasion on the cornea or front of the eye. However, infection would need to be ruled out. If pain and decreased vision persists and does not improve over the next day or two, please call in to see Dr. Adatia. If it is an evening or a weekend, patients are advised to go to the Rockyview Emergency Department in Calgary.
Otherwise, the white of the eye can be red if there is a small bruise around the injection site. Like a bruise, this typically changes color and goes away on its own over the next few weeks.
At the time of the injection, you may notice floating material; that is the medication and it should disperse over hours.
In general, this is a very safe and common procedure.
2. Diabetic Retinopathy.
In diabetes the retina can sometimes receive poor blood flow. When that happens changes can be seen. The first changes are classified as Non-Proliferative Diabetic Retinopathy. What that means is that changes are seen but no “proliferation” or new blood vessels are growing. Typically, hemorrhages are seen in the retina. These changes are monitored for progression over time.
When we see Proliferative Diabetic Retinopathy, then new blood vessels are growing or proliferating in the eye. Although it seems like a great idea that new blood vessels are growing in the eye when there is a lack of blood flow, the problem is that they always grow in the wrong places. These blood vessels are also thin and weak which can lead to breakage leaving the eye full of blood. At this stage treatment is indicated. If the new blood vessels are seen and there is no or minimal hemorrhage or bleeding into the eye then laser can be done in the office or at the hospital. If the eye is full of blood then surgery may be indicated to remove the blood.
Depending on the circumstances, we can sometimes wait for the blood to clear. If laser has previously been done, it can be safe to wait a little while for the blood to clear. If laser has not been done, then it often is indicated to proceed with surgery sooner.
Sometimes new blood vessels can pull on the retina causing a tractional retinal detachment. Depending on where this occurs we may need to proceed with surgery.