Functional relevance and structural correlates of near infrared and short wavelength fundus autofluorescence imaging in abca4-related retinopathy

Abstract

Purpose: To evaluate the functional relevance and structural correlates of autofluorescence (AF) alterations under short-wavelength (SW) and near-infrared (NIR) excitation light in ABCA4-related retinopathy. Methods: In this prospective, cross-sectional case series, 88 eyes of 44 patients with ABCA4-related retinopathy (mean age, 37.6 years; range, 9–77 years) underwent SW-AF and NIR-AF imaging. The AF images were graded for disease characteristic patterns by two independent readers and correlated with alterations in optical coherence tomography (OCT) and impairment of retinal sensitivity along a foveo-papillary line assessed by fundus-controlled microperimetry. Results: A centrifugal sequence of AF patterns from atrophic lesions to homogeneous background was found for both AF modalities. The eccentricity of each AF pattern in NIR-AF was larger compared to those in SW-AF (P, 0.001). Increasing eccentricity of each pattern correlated with increasing retinal sensitivity. The distant border of the zone of hyperfluorescent flecks in SW-AF and hypoautofluorescent flecks in NIR-AF correlated with the margins of the ellipsoid zone loss in OCT (r ¼ 0.979 and r ¼ 0.971, P, 0.001). The expansion of hypofluorescent flecks in SW-AF was associated with the boundaries of external limiting membrane loss (r ¼ 0.933, P, 0.001). Conclusions: SW-AF and NIR-AF revealed a characteristic sequence of AF patterns that correlated with functional and structural alterations, suggesting different stages in disease progression. Translational Relevance: Alterations in NIR-AF exceeded those in SW-AF images, substantiating the hypothesis of different AF origins and suggesting NIR-AF as surrogate marker for early disease-related changes.