Morphologic and Functional Assessment of Photoreceptors in Laser Induced Retinopathy Using Adaptive Optics-SLO and Microperimetry

PURPOSE To assess the cone photoreceptors morphology and associated retinal sensitivity in laser-induced retinopathy (LIR) using adaptive optics Scanning Laser Ophthalmoscopy (AO-SLO) and microperimetry (MP). DESIGN Cohort study. METHODS This study included 13 patients (15 eyes) with LIR and 38 age-matched healthy volunteers (38 eyes). Participants underwent comprehensive evaluations including AO-SLO, MP, and spectral-domain OCT. Lesion morphology, cone density, dispersion and regularity in AO-SLO were assessed and correlated with visual function. RESULTS In AO-SLO images, LIR lesions were predominantly characterized by hyporeflective regions, suggesting potential cone loss at the fovea, accompanied by the presence of sizable clumps of hyperreflective material within these lesions. The average size of lesions in affected eyes was 97,128±107,478μm², ranging from 6,705 to 673,348μm². Compared to the healthy contralateral eye and control group, LIR demonstrated significantly reduced cone density, increased cone dispersion, and notably decreased cone regularity in all four quadrants at 3° eccentricity (all P values <0.05). Lesion morphology in AO-SLO correlated with EZ defects observed in OCT, showing a positive correlation in size (r = 0.84, P<0.001) but not with retinal sensitivities (P = 0.09). Similarly, cone density at 3° eccentricity did not correlate with retinal sensitivities (P = 0.13). CONCLUSIONS AND RELEVANCE The study provides crucial insights into the morphological and functional impacts of LIR on cone photoreceptors, revealing significant morphological changes in cones that do not consistently align with functional outcomes. This research highlights the need for continued exploration into the relationship between retinal structure and function in LIR, and the importance of heightened public awareness and preventive strategies to mitigate the risk of LIR.