Corneal hysteresis measures help predict glaucoma

NEW YORK – Measurements of corneal hysteresis can help the clinician not only diagnose glaucoma, but they provide information on how fast patients are likely to progress, according to Reichert Technologies.

The Ocular Response Analyzer (ORA) provides the biomechanical measurement of corneal hysteresis, a procedure that was recently assigned a CPT code, Reichert’s Dave Taylor told Primary Care Optometry News here at Vision Expo East.

“Corneal hysteresis is an independent predictor of visual field loss in glaucoma,” Taylor explained.

He said that corneal thickness does not dictate IOP, but the IOP CC, or corneal compensated IOP measured by the ORA, can allow more accurate IOP measurements and indicate how fast patients are likely to progress.

Taylor used an analogy to explain the concept of corneal hysteresis. The eye is like a drum, he said, and each beat of the heart beats the “drum.”

“It’s surmised that elevated IOP is causing the drum to be tight,” Taylor said. “The hysteresis measurement indicates the ability of the eye to absorb that shock.

“Corneal hysteresis is considered a structural biomarker of what’s occurring in the optic nerve,” Taylor continued.

Deol and colleagues reported that associations have been found between corneal hysteresis and optic nerve head morphology, including mean cup depth, rim area, cup-to-disc ratio, retinal nerve fiber layer thickness and optic nerve pit.

Taylor added that a high hysteresis measurement is good; an average is 10.

He noted that the ORA was cleared by the FDA in 2004 and introduced commercially in 2006; however, researchers are still learning how this new information is useful. – by Nancy Hemphill, ELS, FAAO

Reference:

Deol M, et al. Curr Opinion Ophthalmol. 2015;26(2):96-102.

Disclosure: Taylor is employed by Reichert.