Impact of Laser Photocoagulation for Peripheral Retinal Degeneration and Breaks on Macular Structure and Function.

PURPOSE: Laser photocoagulation is widely used to treat peripheral retinal pathologies. This study aims to investigate its impact on the macula and identify associated risk factors.

METHODS

This prospective observational study enrolled patients undergoing laser photocoagulation for peripheral retinal degeneration and/or breaks were enrolled. Ocular examinations, including optical coherence tomography (OCT), OCT angiography (OCTA), and multifocal electroretinography (mf-ERG), were conducted at baseline and at 1- and 3-month post-treatment. Data were analyzed using paired t-tests and Pearson's correlation.

RESULTS

Thirty-four eyes from 34 patients were included. The foveal avascular zone area significantly enlarged (Δ = 0.21 ± 0.35mm2, p = 0.038), and mf-ERG implicit times in perifoveal regions were prolonged (R3: Δ = 0.45 ± 0.70 ms, p = 0.027; R5: Δ = 0.85 ± 0.72 ms, p < 0.001) at 1 month following laser photocoagulation, with both parameters returning to baseline by 3 months. Laser photocoagulation also increased thickness in the parafoveal retinal nerve fiber layer (Δ = 1.72 ± 3.33 μm, p = 0.049), inner nuclear layer (Δ = 0.90 ± 1.35 μm, p = 0.014), and full-thickness foveal retina (Δ = 11.2 ± 21.1 μm, p = 0.043), with changes persisting up to 3 months (Δ = 2.74 ± 2.52 μm, p = 0.011; Δ = 0.79 ± 0.79 μm, p = 0.017; Δ = 8.51 ± 8.19 μm, p = 0.014, respectively). Correlation analysis revealed that both the number of laser spots and total laser energy were positively correlated with macular thickness, while the minimum distance between the laser and the fovea was negatively correlated with macular changes.

CONCLUSIONS

Peripheral retinal laser photocoagulation can induce foveal hypoperfusion, macular thickening, and prolonged implicit times. Although most of these changes are generally mild and reversible, macular thickening persisted throughout the 3-month follow-up period. Laser parameters, including the number of spots, energy, and distance from the fovea, are associated with macular changes.