Corneal hysteresis decreases over time

NEW ORLEANS – Researchers found that, over the course of 3 years, corneal hysteresis values in study subjects decreased an average of 0.06 mm Hg per year.

Suchitra Katiyar, MPH, OD, reported here at an Academy of Optometry-sponsored press conference that these findings were consistent with prior studies.

“Corneal hysteresis is the difference in inward/outward applanation pressures and is thought to reflect the ability of the cornea to absorb energy,” Katiyar explained at the press conference. “It is associated with several factors related to glaucoma.”

Katiyar and colleagues evaluated four groups of patients: those with primary open angle glaucoma or POAG (69 patients), glaucoma suspects (23 patients), patients with ocular hypertension (53 patients) and normal controls (42 patients). All visits included measurements with the Ocular Response Analyzer (Reichert), visual field testing, optical coherence tomography and dilated exams annually.

“Patients were required to be seen at least 6 times in 3 years,” Katiyar noted.

Mean corneal hysteresis was lowest in POAG and normal tension glaucoma, while the variability from visit to visit was highest for POAG and ocular hypertension, according to the study abstract.

“Factors associated with change in corneal hysteresis over time included IOP, prostaglandin analog use and worsening glaucoma, suggesting that low corneal hysteresis in glaucoma is at least partially acquired,” Katiyar said.

“A low corneal hysteresis value is an inherent risk factor predisposing one to the risk of glaucoma,” she said. “It would appear that obtaining a baseline value for corneal hysteresis would allow us to predict who is at highest risk for developing glaucoma.” – by Nancy Hemphill, ELS, FAAO

Disclosure: The authors report no relevant financial disclosures.