Quantitative Comparison of Near-infrared Versus Short-wave Autofluorescence Imaging in Monitoring Progression of Retinitis Pigmentosa

Abstract

To quantitatively compare near-infrared autofluorescence (NIR-AF) and short-wave autofluorescence (SW-AF) as imaging modalities used to monitor retinitis pigmentosa (RP) disease progression, measured as a function of hyperautofluorescent ring constriction over time. Retrospective cohort study. NIR-AF and SW-AF images were acquired from 22 participants (44 eyes) at 2 clinic visits separated by an average of 2 years. On the images from each modality, the horizontal and vertical diameters and area of the hyperautofluorescent rings were measured twice, 2weeks apart. A progression rate for each parameter was obtained. Descriptive and comparative statistics were calculated to analyze these parameters and their respective progression rates. At both visits, the hyperautofluorescent ring exhibited a larger horizontal diameter (both visits: P < .001), vertical diameter (visit 1: P < .001, visit 2: P= .040), and ring area (visit 1: P= .001, visit 2: P= .011) in SW-AF vs NIR-AF images. In SW-AF, the horizontal diameter, vertical diameter, and ring area decreased yearly by 168 ± 204μm, 131 ± 159μm, and 0.7 ± 1.1mm2, respectively, while in NIR-AF, they decreased by 151 ± 156μm, 135 ± 190μm, and 0.7 ± 1.0mm2. No difference was observed in these rates between SW-AF and NIR-AF. Similar results were observed in the left eye. In SW-AF and NIR-AF images, similar rates of RP disease progression are observed. As such, NIR-AF may confer more advantages as the primary tool for tracking disease progression over the commonly used SW-AF, given the increased patient comfort and cooperation during imaging.