Effect of Transpupillary Thermotherapy (TTT) for the treatment of choroidal neovascular membrane (CNV) secondary to Age–related macular degeneration (AMD)on patients' central visual fields

Abstract

Abstract: : Purpose:To evaluate the effect of TTT for treatment of exudative AMD, on patients’ metamorphopsia and central visual fields. Methods:Patients with recent onset (<3 months) of occult subfoveal CNV due to AMD underwent TTT using standard parameters (800mW, 3.0mm, 60sec). Metamorphopsia and central visual field defect were measured prior to and 6 months following treatment by means of Amsler chart and automatic perimetry (10.2 visual field test, FASTPACK strategy, white and red stimulus). Results:Thirty two patients completed the study. Despite mild reduction of the size of metamorhopsia by a mean of 23 ±141 squares on Amsler chart, TTT failed to preserve the depth of central scotoma over the study period. Mean deviation in visual field test using white stimulus decreased from 8.4 ± 7.4 db before TTT to –13.0 ± 8.0 db following treatment (p<0.001). Similar results were found when red stimulus was used, with the mean total threshold of the visual field declining from 899 ± 334 to 653 ± 372 db before and after treatment respectively (p<0.001). Conclusions:Although TTT results in stabilization of metamorphopsia in patients with exudative AMD, there is a significant increase in depth of the central scotoma over the first 6 months following treatment. Further controlled studies are required to clarify whether TTT improves the natural course of AMD.

Keywords: age–related macular degeneration • laser • visual fields