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Janette Tang, Nicholas Rinella, Jia Qin, Travis Porco, Austin Roorda, Jacque L Duncan; High resolution measures of disease progression over 36 months in patients with retinal degenerations. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1542.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the inter-visit and inter-ocular variability of Adaptive Optics Scanning Laser Ophthalmoscopy (AOSLO)-derived cone spacing measures in normal eyes and eyes with retinal degenerations (RD) followed for 36 months.
Nine normal subjects and 9 patients with inherited RD, including retinitis pigmentosa (8) and choroideremia (1), were imaged at 3 sessions: 2 baseline visits less than 1 month apart and 36 months later. Cone spacing was measured in multiple regions of interest (ROI) using a density recovery profile histogram method. ROIs were selected at roughly 1 degree intervals throughout the images based on regions in which at least 40 unambiguous cones were visible at 2 baseline visits and were used consistently for subsequent visits. Variability in average cone spacing between visits and between eyes was determined. Standard macular measures, including visual acuity, foveal sensitivity, and spectral-domain optical coherence tomography (SD-OCT) were also measured at each visit.
Cone spacing was measured in 535 ROI in normal subjects and 417 ROI in the RD group. Cone spacing was similar between the 2 eyes of normal (0.0045 arcmin, 95% confidence interval (CI) -0.0067 to 0.016) and RD subjects (-0.025 arcmin, 95% CI -0.010 to 0.050). Cone spacing was similar at the 2 baseline visits; mean absolute difference was 0.017 arcmin in normal (P=0.12) and 0.0038 arcmin in RD (P=0.81) eyes. Cone spacing at 36 months was not significantly different compared to baseline in normal eyes (0.014 arcmin, P=0.12). In RD patients, cone spacing increased by 0.089 arcminutes (P=.031). There were no significant changes in standard clinical measures of disease progression including visual acuity, foveal threshold, and ellipsoid zone (EZ) band width or outer segment (OS) thickness within the central 3 degrees.
Cone spacing increased significantly over 36 months by 6 times more in eyes with RD than in normal eyes, even though no significant change was observed in visual acuity, foveal threshold, EZ band width or OS thickness in this period. Cone spacing measures derived from AOSLO images can be used as a sensitive measure of photoreceptor loss over time in eyes with inherited RD.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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