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K. Ishikawa, S. Ozawa, Y. Ito, M. Kondo, H. Terasaki; Focal Macular Electroretinograms After Photodynamic Therapy Combined With Intravitreal Bevacizumab. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2777.
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© ARVO (1962-2015); The Authors (2016-present)
Retinal function is commonly depressed transiently after photodynamic therapy (PDT) alone. A study from our laboratory using focal macular electroretinograms (FMERGs) found that one of the reasons for the transient reduction in the amplitude was a reduction of choroidal circulation caused by the PDT. The purpose of this study was to determine whether PDT combined with intravitreal bevacizumab (PDT+IVB) can reduce or prevent the transient impaired macular function. In addition, we determined whether a significant correlation existed between the changes in the FMERGs, optical coherence tomography (OCT)-determined morphology, and changes in choroidal circulation.
Thirty-eight eyes that were successfully treated by PDT with intravitreal bevacizumab were studied. FMERGs, OCT, and indocyanine green (ICG) angiography were performed before and after the PDT. The intensity of the diffuse fluorescence within the region of the PDT spot and the unexposed peripapillary retina were measured by densitometry (Topcon IMAGEnet computer system) in the ICG angiograms obtained at 10 minutes three months after the PDT. The ratio of averaged brightness of the retina within the PDT area to that of the peripapillary retina (irradiated/non-irradiated retinal brightness ratio=I/N ratio) was calculated for each angiogram.
The mean amplitudes of the b-wave before, and one week and 3 months after PDT + IVB were 1.99 ± 0.75 µV, 1.87 ± 0.67 µV (mean ± SEM, P>0.05), and 2.39 ± 0.83 µV (P<0.01), respectively. The mean macular thickness within a 3 mm circle centered on the fovea was 336.1 ± 54.2 µm before PDT + IVB and 321.2 ± 63.5 µm one week after PDT + IVB (P<0.01). The I/N ratio of the ICG angiograms three months after PDT + IVB was 0.88 ± 0.1. The correlation between the FMERGs and I/N ratio was not significant.
The use of IVB with PDT mitigates the reduction of the FMERGs and reduced the macular thickness soon after PDT regardless of the degree of impairment of choroidal circulation caused by PDT. The amplitudes of the FMERGs 3 months after PDT + IVB were better than that before the treatment.
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