Macular function evaluated by focal macular electroretinograms after reduced fluence photodynamic therapy in eyes with polypoidal choroidal vasculopathy

The purpose of this study was to evaluate the macular function by measuring the focal macular electroretinograms (ERGs) recorded before and after reduced fluence photodynamic therapy (RFPDT) in patients with polypoidal choroidal vasculopathy (PCV). Eleven eyes of 11 patients with PCV were studied. Their ages ranged from 62 to 85 years with a mean of 74.7 +/- 6.9 years. The exposure time for the RFPDT was reduced to 42 s, so that the total energy of the laser was approximately one-half that of the standard PDT. We measured the visual acuity, foveal thickness, and focal macular ERGs before and after the RFPDT. The follow-up period ranged from 13 to 34 months with a mean of 26 months after the treatment. A significant recovery of vision was seen even at 1 week after the RFPDT (P < 0.005), and the visual acuities improved gradually thereafter (P < 0.0005). The foveal thickness was significantly reduced at 1 week after the treatment (P < 0.005) and then continued to become significantly thinner with time (P < 0.0001). A slight recovery of the a-and b-wave amplitudes was seen postoperatively without a transient reduction in the amplitudes. The b-wave amplitude was significantly larger at 3 months after the treatment than at baseline (P < 0.05). Choroidal hypoperfusion did not develop 3 months postoperatively in the indocyanine green angiograms. Exudative changes recurred in 4 (27%) eyes after 1 year and in 9 (82%) eyes during the follow-up period. RFPDT provided short-term benefits in selected patients with PCV with small lesions. The macular function was retained after RFPDT without a transient decrease in visual function. Further study is needed to determine the long-term efficacy of RFPDT for eyes with PCV.