Long-term therapeutic efficacy of the subthreshold micropulse diode laser photocoagulation for diabetic macular edema.

Purpose: To investigate the long-term efficacy of subthreshold micropulse diode laser photocoagulation (SMDLP) on diabetic macular edema (DME).

Methods: The effects of SMDLP (810 nm) were studied on 56 eyes of 44 patients with DME. Optical coherence tomography-determined foveal thickness and best-corrected visual acuity (BCVA) were evaluated at 1, 3, 6, and 12 months after the SMDLP.

Results: The mean foveal thickness was 504 μm before the SMDLP, and it was significantly reduced to 439 μm at 1 month (P = 0.001), 409 μm at 3 months (P < 0.0001), 358 μm at 6 months (P < 0.0001), and 320 μm at 12 months (P < 0.0001). The mean BCVA at baseline was 0.47 logarithm of the minimal angle of resolution (logMAR) units, and it was not changed significantly at all of the postoperative examinations. Among the 56 eyes, 10 (17.8%) had an improvement of BCVA of >0.2 logMAR units, 36 (64.2%) remained the same, and 10 eyes (17.8%) had a reduction of >0.2 logMAR units at 12 months postoperatively.

Conclusion: Our results indicate that SMDLP has a beneficial effect on DME. However, prospective studies are needed to evaluate this technique in more detail.