Subthreshold Photocoagulation Using Endpoint Management in the PASCAL® System for Diffuse Diabetic Macular Edema

We evaluated subthreshold photocoagulation using endpoint management (EPM) for the treatment of diabetic macular edema (DME). The study enrolled 10 eyes from 10 patients (6 men and 4 women) with DME. The entry criteria included central macular thickness (CMT) ≥ 300 μm and decimal visual acuity (VA) ≤ 0.5. The primary endpoints were VA (logMAR) and CMT at 6 months follow-up. Secondary endpoints included fundus autofluorescence, macular volume (MV), and macular sensitivity (MS). We used the PASCAL Streamline Yellow® (wavelength, 577 nm) system to perform grid pattern laser photocoagulation at 50% of the threshold (size, 100 μm; duration, 0.015 s; spacing, 0.5; and energy, 4.5-7.8 mJ). At 6 months posttreatment, CMT was significantly decreased, while there were no significant changes in macular sensitivity, mean BCVA (logMAR), or macular volume. Autofluorescence imaging revealed no changes after treatment in 6 of 10 eyes. No eyes exhibited subjective symptoms of scotoma after photocoagulation. Optical coherence tomography showed the complete resolution of macular edema in 4 eyes (40%) after a single treatment; MS was increased in all 4 of these eyes at 6 months posttreatment. In conclusion, subthreshold photocoagulation using EPM is safe and effective for DME treatment and preserves MS. This trial is registered with UMIN000012401.