Quantitative Autofluorescence and Visual Function in ABCA4-associated Retinopathy

Abstract

Purpose : To investigate the association between lipofuscin accumulation in the retinal pigment epithelium and retinal function in ABCA4-associated retinopathy.

Methods : In this monocenter prospective case-control study, seventy-seven patients with at least one pathogenic ABCA4 mutation underwent standardized retinal phenotyping and measurement of visual function. Quantitative autofluorescence (qAF) as a surrogate measure for retinal pigment epithelial lipofuscin accumulation was recorded using a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. Measures of qAF were correlated with genotype, structural changes on optical coherence tomography as well as autofluorecence imaging, and retinal sensitivity assessed using fundus-controlled perimetry. One-hundred-ten healthy subjects served as controls.

Results : Patients showed elevated values of qAF compared to controls after adjusting for age. QAF values relative to age-matched controls were highest in the second or third decade of life and decreased thereafter. The qAF increased slower in patients carrying the Gly1961Glu variant compared to patients with other ABCA4 mutations. QAF values within or below the 95% prediction interval of controls were measured in patients with advanced widespread disease manifestation. Retinal sensitivity was reduced in areas with retinal thinning, autofluorescence pattern or outer retinal atrophy, but preserved in regions with normal retinal structure despite elevated qAF intensities.

Conclusions : A consistently increased qAF was identified in patients with mutations in ABCA4, although there was some variability depending on the genotype. The accumulation of lipofuscin had no direct effect on retinal sensitivity.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.