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  • Corneal Stiffness Metrics Signal Glaucoma Progression

    By Lynda Seminara
    Selected By: Stephen D. McLeod, MD
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    Journal Highlights

    Ophthalmology, July 2021

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    Qassim et al. assessed whether corneal stiffness metrics could signal risk of progression in eyes suspected of having glaucoma. They found that progression risk was greatest for eyes with relatively high corneal stiffness and low central corneal thickness (CCT). Hence, corneal stiffness parameters (SPs) and CCT may contribute synergistically to pro­gression, they concluded.

    For this prospective longitudinal study, the researchers included 371 eyes (228 patients) whose optic disc appearance suggested glaucoma—but whose Humphrey visual field (HVF) results were normal. The researchers obtained corneal SPs at baseline and then assessed patients every six months with clinical examinations, OCT scans, and HVF testing. The baseline SP at first applanation (SP-A1) and highest concavity point predicted the out­come measures. Structural progression was determined by OCT-measured thinning of the retinal nerve fiber layer (RNFL) and ganglion cell–inner plexiform layer (GCIPL). Functional progression was established by per­mutation analysis of pointwise linear regression criteria on HVF testing.

    The authors found a strong correla­tion between SPs and CCT. A higher SP-A1 value (suggesting a stiffer cor­nea) signaled faster RNFL thinning (p < .001) and thinner CCT (p = .004) in the follow-up period, which averaged 4.2 years. Eyes with higher SP-A1 and thinner CCT showed accelerated RNFL thinning (0.72 μm/year) relative to eyes with lower values for these metrics. They also were nearly three times more likely to have RNFL decline exceeding 1 μm/year. Findings for GCIPL thinning were similar. High SP-A1 values also were linked to greater risk of visual field progression (p = .002) and thinner CCT (p = .010). The risk of visual field decline was 3.7 times greater for eyes with worse SP-A1 and CCT data.

    These findings augment the body of evidence denoting the importance of considering corneal biomechanics when estimating progression for eyes with suspected glaucoma.

    The original article can be found here.