Purpose: To report the therapeutic outcome of transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularizarion (CNV) in brown retina using a diode-laser with the setting of lower energy level compared to the previous studies on light-pigmented Caucasian patients.
Methods: A total of 19 subfoveal CNVs in 18 patients were treated with TTT. The power of diode-laser was set 160 mW for 1.2 mm beam, 270 mW for 2.0 mm beam, and 400 mW for 3.0 mm beam, and the laser was delivered for 1 min through a slit-lamp mounted-delivery system. Patients were followed up for a mean of 8.8 months (4-12 months). Visual acuity and the fundus change as judged by funduscopic examination and simultaneous fluorescein and indocyanine green angiography were evaluated. Visual acuity was measured by a Japanese standard Landolt visual acuity chart and converted to logarithm of the minimal angle resolution (log MAR) visual acuity for statistical analysis. Improvement or decline in vision was defined as change of more than 0.2 in log MAR visual acuity.
Results: In eyes with minimally classic or occult only CNV, visual acuity improved in two eyes (18%) stabilized in seven eyes (64%) and worsened in two eyes (18%). In eyes with predominantly classic CNV, visual acuity improved in two eyes (25%), stabilized in four eyes (50%) and worsened in two eyes (25%). In all, 15 (84%) eyes of all studied subjects had improvement in exudation. Two (11%) and one (5%) eye(s) were noted to have a significant post-treatment haemorrhage and retinal pigment epithelial tear, respectively.
Conclusion: In patients with brown retinal colour, the treatment outcome of TTT was comparable to that of light-pigmented Caucasian patients with approximately half the laser power energy. Further randomized control studies are warranted.