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What's New in Retina Transpupillary thermotherapy (TTT) – Choroidal neovascularization (abnormal blood vessels under the retina) is the most common cause of severe vision loss in patients with macular degeneration. Until recently, conventional laser treatment was the only treatment available to treat choroidal neovascularization. While conventional laser can successfully eradicate these vessels, it also invariably damages the overlying retina. This results in a permanent blind spot in the treatment area. If the blood vessels are located under the central retina, the resultant blind spot will block central vision. Furthermore, conventional laser is helpful for a relatively small percentage of patients with choroidal neovascularizaiotn from macular degeneration. Transpupillary thermotherapy offers the hope of treating choroidal neovascularization without damaging the overlying retina, thus avoiding the blind spot. The treatment uses a long-wavelength laser which penetrates through the retina to slowly heat the abnormal vessels while avoiding damage to the retina. The treatment remains investigational but appears promising. Many patients who are not eligible for conventional laser may be excellent candidates for transpupillary thermotherapy. The Retina Center is now pleased to offer transpupillary thermotherapy to appropriate patients suffering from choroidal neovascularization. Submacular surgery – Abnormal blood vessels growing under the retina (choroidal neovascularization) and blood under the retina (submacular hemorrhage) can now both be removed thanks to advances in vitrectomy surgery. While the results of submacular surgery for patients with macular degeneration have been disappointing, the technique appears more promising for patients with other conditions (i.e. ocular histoplasmosis). Intravitreal gas for submacular hemorrhage – If you have blood under your retina, it is now possible to displace it from the macula with a newly described outpatient procedure. First, an expansile gas bubble is injected into the eye under local anesthesia (in the office). The patient is then asked to maintain a face down position postoperatively to allow the gas bubble (which floats to the top of the eye) to push the blood out from the center to the more peripheral subretinal space. In rare cases, an additional clot-busting drug known as tissue plasminogen activator may be injected to dissolve the blood clot if the gas alone is not successful. While still experimental, the procedure holds great promise. Laser-induced chorioretinal anastomosis for vein occlusions – Retinal vein occlusions develop when a blockage occurs in one of the small vessels carrying blood from the retina out of the eye. This blockage leads to a pressure build-up upstream from the obstruction site causing small vessels to bleed and leak fluid into the retina. If the central retina is involved in this process, vision can be significantly blurred. In an attempt to provide an alternate exit route for the backed up blood, some researchers have tried creating small holes in the tissues behind the retina with a laser. As the laser spots heal, blood vessels may grow which connect an obstructed retinal vessel with unobstructed vessels in the choroid, a vascular tissue lying in close proximity beneath the retina. In one series, this technique was successful at creating an anastomosis site (alternate route for blood flow) in 1/2 of patients. Complications have also been described including significant bleeding and the formation of abnormal blood vessel growth into the vitreous gel. The technique remains experimental at present. |
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