Laser surgery
The laser is a very bright, finely focused light. It passes through the clear cornea, lens and vitreous without affecting them in any way. Laser surgery shrinks abnormal new vessels and reduces macular swelling. Treatment is often recommended for people with macular edema, proliferative diabetic retinopathy (PDR) and neovascular glaucoma.

Laser surgery is usually performed in an office setting. For comfort during the procedure, an anesthetic eyedrop is often all that is necessary, although an anesthetic injection is sometimes given next to the eye. The patient sits at an instrument called a slit-lamp microscope. A contact lens is temporarily placed on the eye in order to focus the laser light on the retina with pinpoint accuracy.

For macular edema, the laser is applied near the macula in order to reduce fluid leakage. The main goal of treatment is to prevent further loss of vision by reducing the swelling of the macula. It is uncommon for people who have blurred vision from macular edema to recover normal vision, although some will experience partial improvement.

A few people may see laser spots near the center of their vision following treatment. They usually fade with time, but may not disappear completely.

In PDR, the laser is applied to all parts of the retina except the macula (called PRP, or panretinal photocoagulation). This treatment causes abnormal new vessels to shrink and often prevents them from growing in the future. It also decreases the chance that vitreous bleeding or retinal distortion will occur. Panretinal laser has proven to be very effective for preventing severe vision loss from vitreous hemorrhage and traction retinal detachment.

Side effects of panretinal laser surgery may include:

• Temporary blurred vision for days to a few weeks;
• Occasional mild loss of central vision;
• Mild to moderate loss of peripheral vision;
• Decreased night vision.

Multiple laser treatments over time may be necessary. Laser surgery does not cure diabetic retinopathy and does not always prevent further loss of vision. In spite of laser surgery, some people with PDR develop macular distortion or bleeding into the vitreous, causing blurred vision. Vitreous hemorrhage may recur and blood may accumulate faster than the eye can reabsorb it.

Vitrectomy surgery
Vitrectomy is a surgical procedure performed in a hospital or ambulatory surgery center operating room. It is often performed on an outpatient basis or with a short hospital stay. Either a local or general anesthetic may be used.

During vitrectomy surgery, an operating microscope and small surgical instruments are used to remove blood and scar tissue that accompany abnormal vessels in the eye. Removing the vitreous hemorrhage allows light rays to focus on the retina again.

Vitrectomy often prevents further vitreous hemorrhage by removing the abnormal vessels that caused the bleeding. Removal of the scar tissue helps the retina return to its normal location. Laser surgery may be performed during vitrectomy surgery. Vitrectomy surgery may be recommended for:

• Thick vitreous blood in young, insulin-dependent diabetic patients. This is because they are at high risk for traction detachment, which may be hidden behind the blood;
• Thick or repetitive vitreous hemorrhage that does not clear or significantly interferes with the person’s lifestyle;
• Recent traction detachment or distortion of the macula.

To help the retina heal in place, your ophthalmologist may place a gas bubble in the vitreous space. The gas bubble will dissolve in one to eight weeks, depending on the type of gas used. You may be told to keep your head in certain positions while the gas bubble helps to heal the retina. It is important to follow your ophthalmologist’s instructions so your eye will heal properly. You will be advised not to travel by plane or to a high altitude while this bubble is in your eye, since a rapid increase in altitude can raise your eye pressure to dangerous levels and could cause vision loss or even blindness.

Risks of vitrectomy include infection, bleeding, retinal detachment and high pressure in the eye. Cataract formation is uncommon right after surgery; however, most patients often develop a cataract after a number of months or within a few years.

Future treatments
Researchers are studying treatments that target the underlying biochemical mechanisms that cause diabetic retinopathy. One potential future treatment involves the use of VEGF inhibitors, which hinder the growth of new blood vessels. Because leakage from these abnormal blood vessels causes vision loss, preventing their growth could avoid damage to the retina.