AIM: To compare the efficacy of subthreshold micropulse diode(SDM)laser treatment and argon ion laser treatment for diabetic macular edema(DME).

METHODS: A prospective, randomized controlled trial was carried out in 84 patients(99 eyes), in which, 49 eyes received argon ion laser treatment and 50 eyes received SDM laser treatment. The changes in best corrected visual acuity(BCVA), baseline fluorescein angiography and optic coherence tomography measurements were evaluated in both groups. Follow-up visit was over 6 months from baseline.

RESULTS: Ninety-nine eyes(84 patients )complete the study. Six months after treatment, the BCVA improved 22.4% and 20.0% eyes in argon ion laser group and SDM laser group respectively. 55.1% and 58.0% eyes received steady BCVA. Edema partial regression was accounted for 49% in argon ion laser group, while that was 56% in SDM laser group. No statistically significant changes were found in each group.

CONCLUSION: No matter argon ion laser or SDM laser is effective to keep or improve the VA in DME. After 6-month follow-up, there is no statistically significant difference between them.