UC Davis

BACKGROUND AND OBJECTIVE: To determine if subthreshold micropulse laser (SML) therapy can prevent or delay vision loss in diabetic macular edema (DME) with good visual acuity (VA). PATIENTS AND METHODS: Prospective, single-masked, sham-controlled trial in 27 eyes of 19 adult patients with treatment-naïve, center-involved DME, and VA of 20/25 or better. Measures included best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), contrast sensitivity (CS), average threshold on microperimetry, and central subfield thickness (CST). The primary outcome measure was median time to vision loss of 10 letters at any visit or 5 to 9 letters at two consecutive visits ≤ 28 days apart. RESULTS: Eight eyes met vision loss criteria during the 2-year study, with similar proportions for SML (n = 5) and sham (n = 3). Median time to vision loss was 5 months for both groups. At 6 months, there were no statistical differences in BCVA, LLVA, CS, microperimetry threshold, and CST between SML and sham arms (P > 0.05 in all measures). CONCLUSION: In eyes with center-involved DME and good VA, SML did not prevent or delay the vision loss threshold for initiating anti-VEGF therapy. However, these results may be affected by a high rate of early participant dropout from the study. [Ophthalmic Surg Lasers Imaging Retina 2025;56:86-93.].