Subthreshold Pan-Retinal Photocoagulation Using Endpoint Management Algorithm for Severe Nonproliferative Diabetic Retinopathy: A Paired Controlled Pilot Prospective Study

Abstract

<b><i>Purpose:</i></b> The aim of this study was to report the efficacy and safety profile of subthreshold pan-retinal photocoagulation (PRP) using endpoint management (EPM) algorithm compared with conventional threshold PASCAL PRP for the treatment of severe nonproliferative diabetic retinopathy (NPDR). <b><i>Methods:</i></b> This was a prospective, single-center, paired randomized controlled trial of 56 eyes of 28 participants with bilateral symmetric severe NPDR. One eye of the participant was randomly assigned to receive the subthreshold EPM PRP, while the other eye of the same participant received the threshold PASCAL PRP. The primary outcome measures included the difference in the 1-year risk of progression to PDR between 2 groups, and mean changes of the logarithm of the minimal angle of resolution (logMAR) visual acuity (VA). The second outcome measures included central foveal thickness (CFT), 1-year risk of progression to PDR, and visual field (VF) parameters. <b><i>Results:</i></b> The subthreshold EPM PRP group and the threshold PASCAL PRP group had similar 1-year risk of progression to PDR during the 12-month follow-up visits (17.86 vs. 14.29%, <i>p</i> &#x3e; 0.05). Slightly decreased VA was found in both groups (0.08 vs. 0.09 logMAR VA); however, no statistical difference was found for neither group (<i>p</i> &#x3e; 0.05). Similar results were found for thickened CFT for both groups (23.59 vs. 28.34 μm, <i>p</i> &#x3e; 0.05). Specifically, although substantial loss of VF was found in the threshold PASCAL PRP group (<i>p</i> &#x3c; 0.05), no obvious damage to VF was seen in the subthreshold EPM PRP group (<i>p</i> &#x3e; 0.05). <b><i>Conclusion:</i></b> The subthreshold EPM PRP is noninferior to the conventional threshold PASCAL PRP in the treatment of severe NPDR during 12-month follow-up and could be an alternative treatment option for patients with severe NPDR.