Learn more about diabetic eye care

For decades, PDR has been treated with scatter laser surgery, sometimes called panretinal laser surgery or panretinal photocoagulation. Treatment involves making 1,000 to 2,000 tiny laser burns in areas of the retina away from the macula. These laser burns are intended to cause abnormal blood vessels to shrink. Although treatment can be completed in one session, two or more sessions are sometimes required. While it can preserve central vision, scatter laser surgery may cause some loss of side (peripheral), color, and night vision. Scatter laser surgery works best before new, fragile blood vessels have started to bleed. Recent studies have shown that anti-VEGF treatment not only is effective for treating DME, but is also effective for slowing progression of diabetic retinopathy, including PDR, so anti-VEGF is increasingly used as a first-line treatment for PDR.

In some cases of proliferative diabetic retinopathy (PDR), the new blood vessels can cause severe bleeding called a vitreous hemorrhage. This bleeding can block the vision and block the ability of your eye doctor to perform laser treatments. Further, neovascularization can lead to retinal detachment putting the patient at risk for severe vision loss. In these cases, your retinal specialist may recommend surgery to remove the blood or repair the retinal detachment.

In nonproliferative diabetic retinopathy (NPDR), leaking blood vessels can cause diabetic macular edema (DME) and loss of vision. The goal of laser for DME in NPDR is to stop the leakage and prevent further vision loss.  In some cases of severe NPDR, peripheral laser is used to prevent the development of proliferative retinopathy.

If the number of new vessels is great, laser treatment can often prevent loss of vision. The type of laser treatment that is done when there are a lot of vessels is called Panretinal Photocoagulation. This type of laser treatment is usually done in two or more separate sessions. The idea is to use the laser to destroy all of the dead areas of the retina where the blood vessels have been closed. When these areas are treated with the laser, the retina stops manufacturing new blood vessels, and those that are already present tend to diminish or disappear.

Panretinal photocoagulation may have side effects and does not usually improve vision; it is  a means of holding vision stable to prevent further loss. After laser treatments, patients may still have reduced vision or may continue to lose more vision. But if laser is indicated, the chance is that laser treatment will prevent severe loss of vision.

Panretinal photocoagulation is placed in the periphery of the retina, not the center, and side vision may  be diminished. These peripheral  areas are treated  in order to save as much of the central vision as possible and to save the eye itself. Night vision may  also be diminished. After laser, blurred vision is very common. Usually this blur goes away but in a small number of patients, some blur may  continue forever.

DME can be treated with several therapies that may be used alone or in combination.

Anti-VEGF Injection Therapy. Anti-VEGF drugs are injected into the vitreous gel to block a protein called vascular endothelial growth factor (VEGF), which can stimulate abnormal blood vessels to grow and leak fluid. Blocking VEGF can reverse abnormal blood vessel growth and decrease fluid in the retina. Available anti-VEGF drugs include Avastin (bevacizumab), Lucentis (ranibizumab), and Eylea (aflibercept). Lucentis and Eylea are approved by the U.S. Food and Drug Administration (FDA) for treating DME. Avastin was approved by the FDA to treat cancer, but is commonly used to treat a variety of eye conditions, including DME and severe diabetic retinopathy.

Avastin, Lucentis, and Eylea vary in cost and in how often they need to be injected, and treatment will be individualized to the patient.

Focal/grid macular laser surgery. In focal/grid macular laser surgery, small laser burns are made to leaking blood vessels in areas of edema near the center of the macula. Laser burns for DME slow the leakage of fluid, reducing swelling in the retina. The procedure is usually completed in one session, but some people may need more than one treatment. Focal/grid laser may be used with or without anti-VEGF injections.

Corticosteroids. Corticosteroids, either injected or implanted into the eye, may be used alone or in combination with other drugs or laser surgery to treat DME. The Ozurdex (dexamethasone) implant is for short-term use, while the Iluvien (fluocinolone acetonide) implant is longer lasting. Both release a sustained dose of corticosteroids to suppress DME. Corticosteroid use in the eye increases the risk of cataract and glaucoma. DME patients who use corticosteroids should be monitored for increased pressure in the eye and glaucoma.

A vitrectomy is the surgical removal of the vitreous gel in the center of the eye. The procedure is used to treat severe bleeding into the vitreous, and is performed under local or general anesthesia. Ports (temporary water-tight openings) are placed in the eye to allow the surgeon to insert and remove instruments, such as a tiny light or a small vacuum-cutter called a vitrector. A clear salt solution is gently pumped into the eye through one of the ports to maintain eye pressure during surgery and to replace the removed vitreous or blood from diabetic retinopathy. The same instruments used during vitrectomy also may be used to perform laser treatments, remove scar tissue, or to repair a detached retina.

Vitrectomy is usually performed as an outpatient procedure.  After surgery, the eye will be treated with eye drops as the surgeon monitors the healing of the eye.