Long-term evolution of retinal atrophy after focal laser photocoagulation of telangiectatic capillaries: LyoMAC3 study.

OBJECTIVE: To assess the evolution of retinal atrophy secondary to focal laser photocoagulation (FLP) for telangiectatic capillaries (TelCaps) in patients with diabetic macular oedema (DMO) or macular oedema secondary to retinal vein occlusion (MERVO). METHODS: A multicentre retrospective study was conducted in DMO or MERVO patients who underwent at least one FLP session for TelCaps followed for 36 months after FLP. The post-FLP horizontal diameter and surface area of atrophic scars were measured by Optical Coherence Tomography (OCT) and on the OCT infrared image, respectively. The degree of atrophy was quantified on the OCT B-scan. RESULTS: Sixty-nine eyes of 61 patients were included, corresponding to 86 laser scars analysed. The mean scar diameter increased from 315 ± 162 µm at month 1 (M1) to 350 ± 167 µm at M36 (mean increase: 35 µm, p < 0.001). The mean scar area increased from 0.10 ± 0.09 mm2 at M1 to 0.13 ± 0.10 mm2 at M36 (mean increase: 0.03 mm2, p < 0.01) At M1, 2 (2.6%), 74 (96%) and 1 (1.3%) scars were respectively considered "complete Outer Retinal Atrophy" (c-ORA), "incomplete Retinal pigment epithelium and Outer Retinal Atrophy" (i-RORA) and "complete Retinal pigment epithelium and Outer Retinal Atrophy" (c-RORA). At M36, 1 (1.8%), 40 (72.7%) and 14 (25.4%) scars were respectively considered c-ORA, i-RORA and c-RORA. CONCLUSION: The size of retinal atrophy secondary to FLP for TelCaps increases significantly over time. Moreover, retinal atrophy undergoes phenotypic changes. Therefore, it seems imperative to respect a laser impact-free perifoveolar safety zone.