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Hot Laser

By Dr. Shantan Reddy

Thermal laser photocoagulation was first introduced in an attempt to halt the progression of neovascular age related macular degeneration. The Macular Photocoagulation Study (MPS) Group trials assessed laser treatment for CNV in three locations: extrafoveal (≥ 200µm from the geographic center of the foveal avascular zone), juxtafoveal (1-199µm), and subfoveal (extending directly beneath the geographic center of the foveal avascular zone). In each trial, the control group of untreated eyes provided natural history data. Photocoagulation of well-demarcated extrafoveal CNV resulted in a significant reduction in the risk of severe vision loss over the first two years. A recurrence rate of 54% reduced this benefit over the subsequent three years of follow-up. Laser photocoagulation, however, did not result in better vision over a longer period of time. The relative risk of severe visual loss of six or more lines among untreated eyes compared to treated eyes was 1.5 from six months through five years. Photocoagulation of well-demarcated juxtafoveal CNV membranes resulted in a small overall treatment benefit. The benefit was limited because of the high rate of persistence and recurrence (80%) over a five year observation period. Laser photocoagulation of subfoveal CNV was primarily recommended for lesions smaller than two optic discs and with visual acuity below 20/200.  Unfortunately, 82% of treated subjects developed visual loss below 20/200 and the laser photocoagulation of subfoveal CNV is no longer recommended as a primary treatment option for such lesions. In summary, while the MPS group trials demonstrated an effective therapy for extrafoveal CNV, visual results for subfoveal disease and the high rate of foveal recurrence within the first year were disappointing to patients and to their physicians.

Topics and Subtopics: Eye Care

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