Aim: Prospective randomised controlled double-masked trial performed in two centers to compare sub-threshold micropulse diode laser photocoagulation (MPDL) with conventional green laser photocoagulation (CGL) in the treatment of diabetic clinically significant macular oedema (CSME).
Methods: Fifty-three patients (84 eyes) with diabetic CSME were randomly assigned to MPDL (n=44) or CGL (n=40) according to modified ETDRS protocol. Treatments were performed after baseline and re-treatments were allowed at or after the 4 months visit if necessary. Parameters noted included the best corrected visual acuity (BCVA), colour fundus photographs, central retinal thickness using optical coherence tomography (OCT), vision contrast sensitivity with Pelli Robson charts and presence of visible laser scars at baseline, 4 and 12 months. The primary outcome was BCVA at 12 months.
Results: All patients completed 12 months of follow-up after treatment at baseline. There were no statistically significant differences in BCVA, contrast sensitivity and retinal thickness between the two laser modalities at 0, 4 and 12 months. Laser scars were identified at the 12 months visits in 13.9% of the MPDL treated eyes compared to 59.0% of the CGL treated eyes (p<0.001).
Conclusion: Subthreshold micropulse diode laser photocoagulation is equally effective as conventional green laser treatment for CSME.