AMD is the leading cause of vision loss in Americans over age 65. Many risk factors have been identified, including multiple genes which pre-dispose to AMD, as well as external risk factors such as smoking and increased body weight. There are two forms of AMD: DRY AMD involves the accumulation of certain deposits called drusen in the macula. 90% of patients with AMD have the Dry type, and most experience some loss of their central vision and mild distortion, where straight lines look wavy or curved. Some patients with Dry AMD develop significant vision loss from geographic atrophy in the macula. 10% of AMD patients develop the WET form, where abnormal blood vessels, called choroidal neovascular membranes (CNVM), develop in the macula, causing fluid to leak into the macula. This leads to sudden changes in central vision, a dark, blurry spot, and increased distortion.
Patients with AMD are asked to monitor an Amsler grid at least weekly, and to report changes on the grid immediately. AMD patients should stop smoking, maintain a healthy body weight, and eat more dark green, leafy vegetables. The AREDS 2 trial clearly showed the benefit of anti-oxidant vitamins in reducing the risk of progression of AMD in patients with moderate AMD. The AREDS 2 formula is available over the counter without any prescription, and includes:
• 500mg Vitamin C • 400 IU Vitamin E • 80mg Zinc as zinc oxide • 2mg Zeaxanthin • 2mg Copper •10 mg Lutein
Currently, there is no cure for AMD. There is no treatment to reverse Dry AMD. If a patient develops Wet AMD, there is very effective treatment, called anti-VEGF (vascular endothelial growth factor) agents. These anti-VEGF drugs (Avastin, Eylea and Lucentis) have completely revolutionized the treatment of Wet AMD, and prevent progressive vision loss in 90% of patients. Anti-VEGF agents are injected into the vitreous cavity in the middle part of the eye, and repeated injections need to be given for maximum effect.
Diabetic Retinopathy (DR)
DR is the leading cause of vision loss in working-age Americans. High glucose levels in the blood can cause permanent damage to retinal blood vessels, causing them to leak and bleed. Patients report blurry vision, loss of vision or floaters. Non-Proliferative Diabetic Retinopathy (NPDR) represents a mild to moderate form of this condition, but one in which many patients develop Diabetic Macular Edema (DME), in which fluid from leaky retinal blood vessels collects in the macula, causing macular thickening. If DME is not treated, patients develop progressive loss of their central vision. Diabetic patients are encouraged to maintain proper control of their blood glucose levels, BP, and cholesterol, and to work closely with their primary care physicians. Retinal treatment for DME currently involves multiple injections of anti-VEGF agents or steroids into the eye. Focal laser can sometimes be used to treat DME.
The other type of DR is called Proliferative Diabetic Retinopathy (PDR), in which abnormal new blood vessels grow on the retinal surface. This can lead to bleeding in the eye, called vitreous hemorrhage. Treatment for PDR usually involves peripheral laser, and newer studies have shown the effectiveness of anti-VEGF injections compared to laser. Some patients with severe PDR develop scar tissue on the retina, which can lead to a Traction Retinal Detachment (TRD). This requires vitrectomy surgery and laser in the operating room, in order to remove the vitreous and scar tissue from the retinal surface and re-attach the retina.
Floaters and Flashes
The middle part of the eye is filled with a clear gel called vitreous. When we’re young, the vitreous is attached to the retina. Older age or near-sightedness causes the vitreous gel to separate from the retina. Clumps of the separated vitreous float around in the eye. Patients see this as amorphous spots, cobwebs, floaters or veils in their vision. Vitreous traction on the retina, as the gel is trying to separate from the retina, can sometimes cause people to see flashing lights. Sometimes the vitreous gel pulls on the retina with enough traction to tear the retina. This can lead to a retinal detachment.
If someone experiences sudden floaters or flashing lights, they should be examined by their ophthalmologist or optometrist. If a retinal hole or tear is found, they should be referred to a retinal specialist immediately, for laser treatment. Treating a retinal tear with laser is meant to prevent a retinal detachment.
The usual cause of an RD is spontaneous separation of the vitreous from the retina, leading to a retinal hole or tear. This opening in the retina allows liquid from the vitreous cavity to go behind the retina, leading to loss of peripheral followed by central vision. Patients usually complain of a dark curtain or shadow in their vision, usually preceded by floaters and/or flashes.
Treatment for an RD involves either laser retinopexy if the RD is very small, or pneumatic retinopexy in the office, or vitrectomy surgery with laser and gas in the operating room.
Retinal Vein Occlusions
When retinal veins become blocked, pressure builds up in these veins and they bleed in the retina. The resulting hemorrhage and leakage of fluid can cause vision loss due to macular edema (swelling) or macular ischemia (lack of oxygen). There are two types or RVOs: Branch Retinal Vein Occlusions (BRVO) or Central Retinal Vein Occlusions (CRVO). Risk factors include hypertension, high cholesterol, atherosclerosis (hardening of the arteries), smoking and diabetes.
Retinal treatment of a BRVO and CRVO involves anti-VEGF injections into the eye, as well as steroid injections, and laser to the retina, in order to reduce macular edema and prevent loss of vision.These treatments are performed in the office, and may need to be repeated.
Epi-Retinal Membrane (ERM)/Macular Pucker
Sometimes the vitreous gel, which is in contact with the retina, becomes firmly adherent to the center part of the retina, called the macula. This leads to the formation of a layer of tissue on the macula called an Epi-Retinal Membrane. This ERM can contract over time, causing wrinkling or puckering of the normally smooth macular surface, and can lead to some loss of central vision as well as distortion (straight lines looking wavy). ERM formation occurs inside the eye, on its own.
If the ERM is mild, nothing may need to be done. If there is visually-significant progression of an ERM, then vitrectomy surgery in the operating room can be performed to remove the membrane from the underlying
Sometimes the vitreous gel can separate from the retina with enough traction, that it takes a small piece of retina in the center (macula) off with it. This is called a macular hole, and is usually spontaneous. People report a sudden spot in their central vision. An OCT scan is an important tool to assess the macula. Macular holes can be repaired using vitrectomy surgery with membrane peeling and gas in the operating room.