June 13, 2003 — Large–spot size transpupillary thermotherapy (TTT) stabilizes visual acuity in patients with occult choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD), according to the results of a prospective trial published in the June issue of the Archives of Ophthalmology.
"The recent reports on the use of TTT for subfoveal CNV show some success in the treatment of both classic and occult CNV," write Allen B. Thach, MD, and colleagues from the Retinal Consultants of Arizona in Phoenix. "Because occult neovascular membranes are often difficult to precisely define and may originate from more than one [focus], we used a large–spot size diode laser to ensure that the treatment area would cover large, multifocal or diffuse occult CNV."
This nonrandomized, nonmasked case series included 69 patients with AMD treated with TTT, using a diode laser, a spot size of about 3,000 to 6,000 µm delivered over 60 seconds, and a power of 600 to 1,000 mW. All these patients had a predominantly occult choroidal neovascular membrane and an initial visual acuity of 20/400 or better.
Follow-up was at least six months in all patients. At the 6-, 9-, and 12-month follow-up visits, visual acuity was stable or improved in 71% of patients, and 29% lost at least two lines of visual acuity on the Snellen letter chart.
Study limitations include failure to use standardized visual acuity charts and use of only historical controls, which may have induced bias.
"When compared with photodynamic therapy for predominantly occult CNV, TTT seems to have a better success at stabilizing visual acuity, although there have not been any controlled studies with TTT," the authors write. "The exact role of TTT in patients with subfoveal CNV in AMD and the laser treatment variables will only be answered after a large randomized, prospective, multicenter treatment trial is conducted."
Arch Ophthalmol. 2003;817:817-820
Reviewed by Gary D. Vogin, MD
Medscape Medical News © 2003 Medscape
Cite this: Laurie Barclay. Transpupillary Thermotherapy Helpful in Age-Related Macular Degeneration - Medscape - Jun 13, 2003.