Assessment of corneal hysteresis measured by the ocular response analyzer as a screening tool in patients with glaucoma

BACKGROUND: Corneal hysteresis (CH) is used to determine the level of risk of patients developing glaucoma, categorized as suspect, mild, moderate and severe. METHODS: This is a retrospective review of 126 consecutive eyes presenting, for the first time, at a glaucoma subspecialty clinic. All eyes at initial examination underwent measurement of CH and intraocular pressure using the Goldmann applanation tonometry (IOPgat). Eyes were classified as CH<10 (n=51) or CH≥10 (n=75) and categorized into glaucoma suspect, mild, moderate, or severe glaucoma based on 24−2 Humphrey visual field testing. Additional data included number of topical glaucoma medications. RESULTS: Of the eyes classified as a CH<10, 45.5% had moderate or severe glaucoma, and 11.8% of eyes with a CH≥10 had moderate or severe glaucoma. In the CH≥10 group, the mean IOPgat was 19.5 mmHg ± 4.72 mmHg (P<0.01) on 1 ± 1.26 (P<0.01) medications in the moderate/severe glaucoma group and 20.13 mmHg ± 4.95 mmHg (P<0.01) on 0.60 ± 0.95 (P<0.01) medications in the glaucoma suspect/mild glaucoma group. In the CH<10 group, mean IOPgat was 20.47 mmHg ± 7.56 mmHg (P<0.01) on 1.79 ± 1.17 (P<0.01) medications in the moderate/severe glaucoma group. Mean IOPgat was 17.54 mmHg ± 5.48 mmHg (P<0.01) on 0.63 ± 0.83 (P<0.01) medications in the glaucoma suspect/mild glaucoma group. CONCLUSION: Moderate to severe glaucoma is 2.9 (P<0.01) times more likely to occur in eyes that measure a CH<10 compared to eyes that measure a CH≥10. Although not statistically significant, suspect or mild glaucoma is more common in eyes that measure a CH≥10. Eyes in the CH<10 moderate/severe glaucoma group had statistically significant higher IOPgat (P<0.01) compared to the CH<10 suspect/mild glaucoma group. Measuring CH at initial presentation can help predict the severity of glaucoma.