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Daniel Galles, David G Birch, Yi-Zhong Wang; The Rate of Progressive Loss of Central Subfield Thickness (CSFT) and Visual Function in Stargardt Macular Dystrophy (STGD). Invest. Ophthalmol. Vis. Sci. 2019;60(9):1887. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
ProgStar studies have shown visual acuity (VA) to be a poor indicator of STGD progression due to its slow deterioration rate (Kong et al, 2018). Comparatively, we have shown that shape discrimination hyperacuity (SDH) progresses more rapidly than VA during earlier stages of STGD (Wang et al, 2009 ARVO). However, the relationship between SDH and CSFT, an anatomical gauge for disease progression as determined by Spectral Domain-Optical Coherence Tomography (SD-OCT), has not previously been explored. Here, we examined the relationship between CSFT, VA, and SDH in patients with STGD. The rates of progression of CSFT and visual function were also assessed for earlier and more advanced stages of STGD.
The eyes with worse VA of 18 patients with STGD were selected on the basis of 20/200 or better visual acuity and having at least 4 years of follow up. All patients had at least 1 mutation of ABCA4. This cohort was divided at the median initial CSFT of 180 μm and the rates of progression between earlier (≥180 μm, n=10) and more advanced (<180 μm, n=8) stages of disease were compared. SDH was performed using deformed circular shapes. SD-OCT volume scans were obtained using the Heidelberg Spectralis, and layer segmentation was manually corrected on Heidelberg Eye Explorer.
Cross-sectional linear regression across 18 eyes at initial visit showed significant correlation of CSFT with VA (r=0.52, p<0.027) and SDH (r=0.65, p<0.004). The 4-year change of CSFT and SDH showed a borderline significant correlation (r=0.47, p<0.058). Yearly rates of change are listed in Table 1. A greater yearly rate of change was shown for patients with initial CSFT ≥180 μm vs <180 μm for CSFT (p<0.041) and SDH (p<0.015). The difference in yearly rate of change of VA was not significant.
These results further demonstrate that shape discrimination hyperacuity changes more rapidly than VA in earlier stages of STGD, regardless of whether the earlier stage was defined by initial VA or CSFT. Additionally, the results show that CSFT, alongside SDH, can be used as an effective biomarker to track progression of STGD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Table 1. Yearly Rate of Change of CSFT, VA, and SDH
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