Subthreshold micropulse laser for subretinal fluid after vitrectomy in myopic traction maculopathy: a pilot randomized controlled trial

To evaluate the effectiveness and safety of subthreshold micropulse laser (MPL) in patients with residual subretinal fluid (SRF) after vitrectomy for myopic traction maculopathy (MTM). This was a prospective, pilot randomized controlled trial. We recruited eyes with residual SRF≥200 μm on OCT at 1-month follow-up after vitrectomy for macular hole retinal detachment (MHRD) and macular schisis with foveal detachment (MSRD). Forty eligible patients were randomized to control and MPL group in a 1:1 allocation ratio. Patients in the MPL group received MPL treatment 1-month after surgery by a same doctor and the procedure was repeated at 1-month intervals when necessary. Follow-up endpoint was defined as either complete absorption of subretinal fluid (SRF) or a minimum postoperative observation period of 6 months. The median follow-up time was 6 months (range: 3-28 months). Postoperatively, BCVA was significantly improved, and macular thickness was significantly reduced (P < 0.001) compared with preoperative baseline. The patients in the MPL group received 2.05 ± 0.89 (range 1-3) times of MPL. The Kaplan Meier curve showed a trend that the MPL group had better SRF absorption, but the difference is not significant between the two groups (P = 0.33). No severe complications in both groups during the follow-up. MPL is a safe non-invasive procedure in pathologic myopia patients. The limited therapeutic effect of MPL on SRF absorption may reflect the compromised RPE function resulting from progressive thinning and atrophy in highly myopic eyes.