Subthreshold Micropulse Laser and Conventional Subthreshold Laser in Diabetic Macular Edema

PURPOSES: To compare the short-term morphological and visual function changes after subthreshold micropulse laser photocoagulation (SMLP) and conventional subthreshold laser photocoagulation (SLP) in eyes with diabetic macular edema (DME). METHODS: This prospective, paired, randomized controlled trial comprised 66 eyes from 33 patients with clinically significant diabetic macular edema (CSME). Each patient's bilateral eyes were randomized, with one receiving SMLP and the other SLP. All patients underwent best corrected visual acuity (BCVA), slit-lamp biomicroscopy, fundus photo, optical coherence tomography, fundus autofluorescence (FAF), and microperimetry at baseline and at the 1-, 3-, and 6-month follow-ups. RESULTS: From baseline to month 6, no significant difference was observed between the two groups in terms of BCVA, central macular thickness (CMT), central choroidal thickness, increased FAF area or macular sensitivity (all p>0.05). However, significant CMT reduction began earlier (month 3) in the SMLP group than in the SLP group (month 6) (all p<0.05). CONCLUSION: Over a 6-month period, SMLP appears to be as effective as conventional SLP in treated eyes with CSME, while potentially causing less retinal damage.