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Eleonora M Lad, Wendi Liang, Glenn J Jaffe, Zengtian Deng, Jessica Loo, Dibyendu Mukherjee, Sina Farsiu; The RUSH2A study: Baseline microperimetry and SD-OCT measures. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2435.
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© ARVO (1962-2015); The Authors (2016-present)
To study the natural history of retinal degeneration related to disease-causing sequence variants in the USH2A gene, the Foundation Fighting Blindness Consortium is conducting a 4-year multicenter, international natural history study titled Rate of Progression in USH2A-related Retinal Degeneration (RUSH2A). Herein we evaluate baseline mesopic microperimetry (MP) and spectral domain optical coherence tomography (OCT) metrics and their relationships with other baseline characteristics.
One eye of each patient had MP with a MAIA system and OCT was tested on both eyes with a Heidelberg Spectralis unit. General linear models were used to assess the association between demographic and clinical characteristics, including gender, race, age, disease duration, smoking, use of dietary supplements, MP mean sensitivity, and OCT ellipsoid zone (EZ) area. The association between MP mean sensitivity and OCT EZ with visual acuity (VA), and central subfield thickness (CST within the center 1mm) was assessed using Spearman correlation coefficients.
All study participants (N=127) had OCT, while MP was obtained at selected sites (N=91). Comparing participants with Usher syndrome type 2 (USH2, N=80) to autosomal recessive non-syndromic RP (ARRP, N=47), the central structural measures of OCT EZ (3.1±5.7 mm2 vs 4.3±5.6 mm2, p=0.26) and CST (253.1±57.5 µm vs 263.6 ± 32.9 µm, p=0.26) were similar. Longer disease duration was associated with smaller OCT EZ (p<0.001) and lower mean sensitivity (p=0.01). Comparing MP in USH2 participants (N=55) to those with ARPP (N=36), mean sensitivity was similar by diagnosis (5.4 ± 4.9 dB vs 6.7± 5.1 dB, p=0.22). Point-wise sensitivity from repeated MP tests confirmed that central points (within 10-degree) had better sensitivity than peripheral ones (Figure 1). Better VA, larger OCT EZ area, and larger CST were associated with greater MP mean sensitivity (r>0.3 and p<0.01). Better VA and larger CST were also associated with larger OCT EZ area (r>0.6 and p<0.001).
The baseline RUSH2A data revealed similar OCT and MP metrics between the USH2 and ARRP participants. Longer disease duration was associated with more severe abnormalities in retinal structure and function. MP and OCT measures may be useful to monitor disease progression in future studies of USH2A-mediated disease.
This is a 2021 ARVO Annual Meeting abstract.
Legend: The red dotted line denotes the 10-central degree. The plot only includes eyes with 3 valid tests
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