To evaluate the effects of radial optic neurotomy (RON) on retinal circulation in patients with central retinal vein occlusion (CRVO) by indocyanine green (ICG) videoangiography and a computer- assisted image analysis. An interventional case series. RON was performed in 15 eyes of 15 patients with CRVO. Within 72 hours before the surgery and at 3 months after the surgery, ICG videoangiography was performed with a scanning laser ophthalmoscope, and the images were transferred to a computer. Two measurement points were selected, one on a main retinal artery close to the optic disk and the other on the corresponding retinal vein. At each point, fluorescence intensities were serially measured, and dye dilution curves were obtained. Retinal circulation times (△ T50) before and after the surgery were calculated. Mean preoperative △ T50 was 6.46 ± .1.36 seconds, and mean postoperative △ T50 was 6.80 ± .2.50 seconds. In 8 of 15 eyes, △ T50 decreased by 6.8% to 29.6% after the surgery. In the seven eyes that developed chorioretinal anastomosis (CRA) at the site of RON, △ T50 decreased after the surgery. In contrast, △ T50 decreased postoperatively in only one of the eight eyes without CRA. Best- corrected visual acuity improved significantly after the surgery in the group of eyes with improvement in △ T50, but not in the group of eyes without improvement in △ T50. Some degree of retinal circulation improvement occurred in approximately half of these eyes, which appears to be correlated with the development of CRA. To evaluate the effects of radial optic neurotomy (RON) on retinal circulation in patients with central retinal vein occlusion (CRVO) by indocyanine green (ICG) videoangiography and a computer- assisted image analysis. An interventional case series. of 15 patients with CRVO. Within 72 hours before the surgery and at 3 months after the surgery, ICG video angiography was performed with a scanning laser ophthalmoscope, and the images were transferred to a computer. Two measurement points were selected, one on a main retinal At each point, the fluorescence intensities were serially measured, and the dye dilution curves were obtained. Retinal circulation times (ΔT50) before and after the surgery were calculated. Mean preoperative △ T50 was 6.46 ± .1.36 seconds, and mean postoperative △ T50 was 6.80 ± 2.50 seconds. In 8 of 15 eyes, △ T50 decreased by 6.8% to 29.6% after the surgery In the seven eyes that developed chorioretinal anastomosis (CRA) at the site of RON, Δ T50 decreased after the surgery. In contrast, Δ T50 decreased postoperatively in only one of the eight eyes without CRA. Best- corrected visual acuity improved significantly after the surgery in the group of eyes with improvement in △ T50, but not in the group of eyes without improvement in △ T50. Some degree of retinal circulation improvement occurred in approximately half of these eyes, which appears to be correlated with the development of CRA .