Researchers from New York have reported a new association between low corneal hysteresis (CH) and optic disc hemorrhage, possibly suggesting that corneal biomechanical properties are important to glaucomatous optic neuropathy. Their study found that eyes with optic disc hemorrhage had lower CH and higher vertical cup-to-disc ratio measurements.
The researchers identified and analyzed 49 patients with unilateral disc hemorrhage. Compared with fellow non-hemorrhage eyes, eyes with optic disc hemorrhage had lower CH (8.7±1.9 vs. 9.2±1.7), higher IOP (15.6±3.6 vs. 14.3±4.1) and greater vertical cup-to-disc ratio (0.79±0.13 vs. 0.68±0.23). The eyes in the two groups were similar with respect to central corneal thickness, number of clock hours of beta zone parapapillary atrophy extent, presence of neuroretinal rim notching, peak IOP and visual field damage. The team found only CH and vertical cup-to-disc ratio predicted the laterality of the disc hemorrhage.
The researchers believe their findings suggest that, although the level of IOP and degree of glaucomatous optic neuropathy are related to disc hemorrhage, ocular biomechanics may be equally relevant to an eye’s susceptibility. As disc hemorrhage may be the result of glaucoma damage, the researchers believe it is possible that reduced CH may be an indicator of glaucoma-related biomechanical stress.
|Radcliffe NM, Tracer N, De Moraes CGV, et al. Relationship between optic disc hemorrhage and corneal hysteresis. Can J Ophthalmol. December 23, 2019. [Epub ahead of print].|