Miscalibration and severe complications after diode laser cyclophotocoagulation: two case reports

Because two similar transscleral cyclophotocoagulation diode lasers with identical power & duration settings induced significantly different postoperative inflammation, we wanted to compare the real output of both lasers. Using a Power/Energy Meter (Fieldmaster) we compared the output of the two lasers (the Iridis [Quantel Medical] and the Iris Medical [OcuLight SLx]) at different energy levels. At a setting of 600, 1000, 1400, 1700, 2000 and 2500 mW, the measured output for the Iridis and Iris Medical diode laser were respectively 685 and 400 mW, 970 and 650 mW, 1470 and 875 mW, 1700 and 1000 mW, and 1990 compared to 1000 mW. On the average the output of the Iridis laser was correct and the output of the Iris Medical laser was 40% lower than the setting. Overtreatment and severe complications occurred with the Iridis laser because the manufacturer recommended using wrong power settings based on the Iris Medical laser, which was undercalibrated. The calibration of cyclophotocoagulation diode lasers should be performed prior to use when changing to a new device and whenever over- or undertreatment is observed.