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Ajoy Vincent, Eleonora M Lad; Microperimetry and optical coherence tomography measures over 2 years in the RUSH2A study: annual rates of change from mixed effects modeling. Invest. Ophthalmol. Vis. Sci. 2022;63(7):3339 – F0148.
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© ARVO (1962-2015); The Authors (2016-present)
Mean retinal sensitivity (MS) from microperimetry (MP), and ellipsoid zone (EZ) area and central subfield thickness (CST) from optical coherence tomography (OCT) are quantitative measures that provide insight to functional and structural function in inherited retinal degenerations (IRDs). There are few available estimates for their rates of change in IRDs. Here we provide estimates of change over 2 years from the Rate of Progression in USH2A-related Retinal Degeneration (RUSH2A) study based on these measures using mixed effects models.
In this prospective multicenter study, participants with visual acuity ≥20/80, stable fixation, and kinetic visual field of ≥10° in the study eye had MP and OCT testing at baseline, 1, and 2 years. MP was performed only in centers that had available equipment, while OCT was performed in all participants. Summary measures were MS from MP, and EZ area and CST from OCT. CST values were excluded when intraretinal cystoid spaces were detected. Mixed effects models were used to estimate the annual rates of change and percentage rates of change using log transformed data with 95% confidence intervals (CI). Models were applied to all eyes and to a restricted group of eyes with baseline levels above specific thresholds: >2 dB for MS and >1 mm2 for OCT EZ area to mitigate floor effects. A model down-weighting outlier rates of change was also applied.
102 eyes were included. The average decline in MS [N=85] was 0.42 (0.27, 0.57) dB/year (Table 1) or 8.8 (6.2, 11.3)%/year (Table 2) in the entire cohort, and 0.51 (0.32, 0.69) dB/year or 8.8 (6.1, 11.5) %/year in the restricted cohort [N=69]. The average decline in EZ area for the entire cohort [N=100] was 0.11 (0.02, 0.20) mm2/year or 1.2 (-1.1, 3.6) %/year vs 0.15 (0.03, 0.27) mm2/year or 0.8 (-1.0, 2.6) %/year in the restricted cohort [N=72]. The decline in CST was 2.05 (1.07, 3.02) µm/year or 0.8 (0.4, 1.2) %/year in the entire cohort [N=63] when no cystoid spaces were detected. Down-weighting outliers reduced the estimated decline of MS and EZ, but not CST, compared to the unadjusted model.
Based on 2 years of follow-up in RUSH2A, estimates of the annual rates of decline in MP and OCT measures were affected by the baseline values of the eyes included in the analysis. Down-weighting outliers reduced the estimated decline of MS and EZ, but not CST.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.
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