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B Falsini, F Focosi, M Piccardi, E Pirozzi, F Coccimiglio, F Molle, C Manganelli, MA Mainster; Focal ERG Monitoring of Transpupillary Thermotherapy: Potential Use for Optimizing Subthreshold Laser Treatment of Choroidal Neovascularization . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4409.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the potential use of focal electroretinography for monitoring and optimizing transpupillary thermotherapy (TTT) for occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD). Methods: We evaluated 24 eyes of 24 patients undergoing TTT for occult CNV due to AMD. TTT was performed according to the Reichel et al. protocol (1999). A 630-nm photocoagulator aiming beam was modified for use as a 41-Hz square-wave focal electroretinogram (FERG) stimulus. It was presented on a light-adapting background, using a Goldmann-type lens (visual angle, 18°; mean luminance, 100 cd/m2). FERGs were continuously monitored before, during and after TTT. The amplitude and phase of the FERG's fundamental harmonic were measured. TTT outcomes were evaluated one and three months after treatment by visual acuity testing, ophthalmoscopy and fluorescein angiography (FA). Results: Stabilization or improvement of visual acuity occurred in 23 of 24 eyes treated with TTT. A reduction in exudation was observed in the FAs of 14 of the 24 eyes. There were no suprathreshold or adverse clinical events. Mean FERG amplitudes decreased transiently during TTT (-16.4% ± 6.6, p < 0.05), returning to pre-TTT values within 60-sec after treatment ended. TTT did not alter FERG phase. Post-TTT changes in visual acuity (i.e., the ratio of post- to pre-TTT visual acuity) were positively correlated (r = 0.55, p = 0.02) with FERG amplitude changes (i.e., the percentage change from the pre-TTT value) during TTT. The best angiographic outcomes were associated with the smallest decreases in FERG amplitude during TTT (p = 0.01). Conclusion: In patients undergoing TTT for occult CNV in AMD, improved visual and angiographic outcomes are correlated with lower reductions in intraoperative FERG amplitudes, suggesting the potential use of focal electroretinography for monitoring and modulating laser parameters for individual eyes and macular lesions.
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