Abstract
Purpose :
Diabetic macular edema (DME) is often managed with intravitreal injections in eyes with visual impairment of 20/32 or worse, while eyes with center-involved DME and good visual acuity (20/25 or better) can be managed with observation alone, based on findings from the DRCR Retina Network Protocol V. The prospective microPulse laser for Suppression of diabetic macular Edema (PULSE) study evaluates the role of subthreshold micropulse laser (SML) to improve or stabilize visual acuity and retinal anatomy to prevent the need for anti-VEGF therapy compared to observation alone.
Methods :
We performed a prospective, single-masked, sham-controlled trial in 27 eyes of 19 adult patients with type 2 diabetes mellitus (mean age = 56.2 years) and treatment-naïve, center-involved DME and good visual acuity (20/25 or better) randomized 2:1 to SML (n = 16) or sham laser (n = 11). Patients were evaluated at 1 month, and then every 3 months until 24 months to measure best-corrected visual acuity (BCVA), low luminance visual acuity (LLVA), contrast sensitivity (CS), and central subfield thickness (CST) on optical coherence tomography (OCT). The primary outcome was the median time to vision loss criteria of 10-letters at any visit or 5-9 letters at 2 consecutive visits ≤28 days apart. Secondary outcomes include mean change in BCVA, LLVA, contrast sensitivity, and CST.
Results :
Among enrolled eyes, 8 eyes met vision loss criteria during the 2-year study, with similar proportions between SML (n = 5) and sham (n = 3). The median time to vision loss was 5 months for both treatment groups, with no statistical difference (P = 0.764). A large portion of patients (n = 11) did not complete the entire 24-month study period, so secondary outcomes were only analyzed to 6 months. There were no statistical differences in BCVA, LLVA, CS, and CST between SML and sham arms at baseline (P > 0.05 in all measures). At month 6, mean BCVA was 79.4 and 83.9 letters (P = 0.344), LLVA was 30.7 and 40.1 letters (P = 0.189), CS was 1.54 and 1.61 (P = 0.966), and CST was 357.8 μm and 356.9 μm (P = 0.508) for the SML and sham groups, respectively.
Conclusions :
In eyes with center-involved DME and good visual acuity, SML did not appear to prevent or delay the vision loss threshold for initiating anti-VEGF therapy. However, these results may be impacted by a high rate of early dropout from study enrollment.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.