Corneal biomechanical parameters and functional damage in glaucoma may have weak relationship

An observational, cross-sectional study showed a weak relationship between corneal biomechanical parameters and measures of structural and functional damage in glaucoma.

Researchers investigated the association between corneal biomechanical parameters and glaucoma severity in 299 eyes of 191 patients; 148 eyes had confirmed glaucoma and 151 eyes had suspect glaucoma.

The Ocular Response Analyzer (Reichert) was used to measure corneal hysteresis and corneal resistance factor in all subjects.

Retinal nerve fiber layer thickness was measured by spectral-domain optical coherence tomography in 146 eyes (84 suspect eyes and 62 glaucoma eyes) of 92 participants and by GDx ECC imaging in 204 eyes (98 suspect eyes and 106 glaucoma eyes) of 142 participants.

Corneal hysteresis and corneal resistance factor were positively associated with visual field mean defect (P < .01). The association between corneal resistance factor and mean defect was significant on multivariable analysis (P < .01), but it was not significant between corneal hysteresis and mean defect on multivariable analysis.

There was a weak association between corneal hysteresis and corneal resistance factor and average retinal nerve fiber layer thickness in the GDx ECC group but not in the spectral domain OCT group.

“We found that [corneal hysteresis] and [corneal resistance factor] were positively associated with more severe visual field damage in univariable analysis but only [corneal resistance factor] remained independently associated with [mean defect] and [pattern standard deviation] after adjustment for relevant demographic and ocular parameters,” the study authors said. “Prospective longitudinal studies are needed to investigate the relationship between corneal biomechanics and long-term risk of glaucoma progression.”