Retinal Laser Therapy Mechanisms, Innovations, and Clinical Applications

Retinal laser therapy has been a mainstay for treating proliferative diabetic retinopathy, retinal vascular disease, and retinal breaks since 1961. However, conventional millisecond photocoagulation can cause permanent scarring and procedure discomfort, motivating the development of damage-sparing approaches that preserve the neurosensory retina. Clinically, panretinal photocoagulation remains effective for proliferative disease but trades off peripheral visual field and night vision. This review synthesizes development, mechanisms, and clinical evidence for laser modalities, including short-pulse selective retinal therapy (SRT), subthreshold diode micropulse (SDM), and pattern-scanning photocoagulation. We conducted a targeted narrative search of PubMed/MEDLINE, Embase, Web of Science, and trial registries (1960–September 2025), supplemented by reference list screening. We prioritized randomized/prospective studies, large cohorts, systematic reviews, mechanistic modeling, and relevant preclinical work. Pulse duration is the primary determinant of laser–tissue interaction. In the microsecond regime, SRT yields retinal pigment epithelium (RPE)-selective photodisruption via microcavitation and uses real-time optoacoustic or OCT feedback. SDM 100–300 µs delivers nondamaging thermal stress with low duty cycles and titration-based dosing. Pattern-scanning platforms improve throughput and tolerance yet remain destructive photocoagulation. Feedback-controlled SRT shows anatomic/functional benefit in chronic central serous chorioretinopathy and feasibility in diabetic macular edema. SDM can match threshold macular laser for selected DME and may reduce anti-VEGF injection burden. Sub-nanosecond “rejuvenation” lasers show no overall benefit in intermediate AMD and may be harmful in specific phenotypes. Advances in delivery, dosimetry, and closed-loop feedback aim to minimize collateral damage while retaining therapeutic effect. Key gaps include head-to-head trials (SRT vs. PDT/SDM), standardized feedback thresholds across pigmentation and devices, and long-term macular safety to guide broader clinical adoption.