Study: Higher contrast thresholds for vanishing optotype rec
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Researchers aimed to explore the impact of glaucomatous macular damage, specifically retinal ganglion cell (RGC) loss, on macular pattern vision measured by the vanishing optotype (VO) recognition contrast threshold.

The study included 72 patients with primary open-angle glaucoma and 36 safe controls. Each participant's VO recognition contrast thresholds were calculated at 16 pre-determined test locations across the central 5° visual region (VF). The Humphrey Field Analyzer's macular threshold test was used to assess macular sensitivity (MS). Spectral domain optical coherence tomography was used to calculate the thickness of the macular RGC plus inner plexiform layer (GCIPL).

Results:
--The VO contrast threshold demonstrated weak-to-moderate correlations (rho=-0.275 to -0.653) with MS.

--There was a significantly higher VO contrast threshold in glaucoma group. At similar levels of MS, patients with glaucoma with GCIPL damage showed remarkably higher VO contrast thresholds than those with preserved GCIPL.

--The structure–function relationships between VO contrast threshold and GCIPL thickness (rho=-0.725 to -0.802) were remarkably stronger than those between MS and GCIPL thickness (rho=0.210 to 0.448).

--VO contrast threshold showed stronger correlation with average GCIPL thickness (rho=?0.362 to ?0.778) than MS (rho=0.238 to 0.398) at multiple test locations in glaucoma group.

In fovea-around VF, glaucomatous eyes have higher contrast levels for VO recognition. The VO contrast threshold is more vulnerable to RGC harm if the structure–function relationships are stronger.

Source: https://bjo.bmj.com/content/early/2021/05/23/bjophthalmol-2021-318972?rss=1
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