Neelakshi Bhagat, MD (Newark, NJ), Ruben Grigorian, MD (Newark, NJ), Nilang Patel, MD (Newark, NJ), Marco A. Zarbin, MD, PhD (Newark, NJ), Monique Roy, MD (Newark, NJ), Arthur Tutela, MD (Newark, NJ)


To evaluate the efficacy of Subthreshold Micropulse Diode Laser Photocoagulation (SMDLP) in the treatment of diabetic clinically significant macular edema (CSME), and to compare it to the standard treatment, Conventional Argon Laser Photocoagulation (CLP).


Forty-four phakic eyes with CSME in 27 diabetic patients were prospectively enrolled in the study, randomized in a 1:1 ratio to receive either SMDLP or CLP. Grading of CSME was based on the ETDRS classification. The following parameters were measured at each visit: best-corrected visual acuity (BCVA; Central 10-2 Humphery visual field examination; scanning laser ophthalmoscope microperimetry and optical coherence tomography of the macula. In both study arms, the determination to perform additonal laser treatment was based on the presence of residual CSME as determined by clinical biomicroscopic examination at 4 month follow-up visit.


Eight eyes of eight patients who did not return for the first 4-month follow-up visit were excluded from statistical analysis. 19 eyes received SMDLP and 17 eyes received CLP. At baseline, pre-treatment mean BCVA in SMDLP and CLP groups were 0.20 and 0.25 logMAR, respectively. Final mean BCVA in SMDLP and CLP groups were 0.28 and 0.26 logMAR, respectively. CSME resolved in thirteen (68%) out of 19 eyes in SMDLP group and in twelve (70.5%) out of 17 eyes in CLP group. Paracentral scotoma developed posttreatment in 17% of eyes in the SMDLP group as compared to 28% of eyes in the CLP group.


SMDLP appears effective in the treatment of CSME, with results comparable to or better than those obtained with CLP. The risk of scotoma development was lower with SMDLP than CLP. SMDLP may be a safer laser modality than CLP, especially when the treatment is required within the foveal avascular zone, or in patients who may have already developed extensive retinal pigment epithelium hyperplasia.