Transpupillary thermotherapy for occult subfoveal choroidal neovascularization: a 1-year, prospective randomized pilot study

Purpose: To evaluate the 1-year effect of transpupillary thermotherapy ( TTT) on occult choroidal neovascularization membranes (CNV). Methods: In this prospective, randomized, controlled pilot study of 28 patients with occult or minimally classic (< 10%) neovascularization membranes with a diameter less than 4500 mm, 19 patients were treated with TTT, while nine received sham treatment. Outcome measures were membrane diameter, visual acuity and reading ability. Results: The median age of patients randomized to TTT was 78 years (range 24 years); that of patients randomized to sham was 79 years ( range 9 years). There was no difference regarding membrane diameter at baseline between the two groups; the median membrane diameters were 3400 mm (range 2400 mm) in the TTT group and 3200 mm (range 2300 mm) in the sham group (p = 0.639). Visual acuity (VA) was similar, with a median of 0.2 (minimum-maximum 0.08-0.5) in the TTT group and a median of 0.16 (min-max 0.10-0.32) in the sham group. A total of 21 patients were followed for 1 year, 13 in the TTT group (2.7 treatments/patient) and eight in the sham group. Membrane diameter increased in both groups, by a median of 350 mu m (range 1600 mm) in the TTT group and 800 mm (range 1700 mm) in the sham group (p = 0.414), respectively, and there was a loss in VA of >= 15 letters in 5/13 patients (38%) in the TTT group compared with 2/8 patients (25%) in the sham group (p = 0.266). Reading ability deteriorated equally over time in both groups. Seven patients were lost to follow-up due to reluctance to continue in the study (n = 4) or development of a classical component > 50% (n = 3) requiring photodynamic therapy (PDT). Conclusion: The results from this randomized, prospective pilot study of TTT for occult CNV did not indicate that TTT has a beneficial effect on visual outcome 1 year after treatment compared with the visual outcome that results from the natural course of the disease. The small study size limits statistical power and results from large control studies are needed.