Abstract
Purpose :
To compare biomechanical metrics between eyes of subjects with asymmetric glaucoma (ASYMM) and those with symmetric glaucoma (SYMM).
Methods :
A total of 46 subjects were prospectively recruited. ASYMM was defined as C/D difference > 0.1 between eyes (C/D difference range 0.12 to 0.65) and SYMM was defined as a C/D difference <= 0.1 between eyes (C/D difference range 0 to 0.1). There were 32 eyes of 16 subjects in the ASYMM group and 60 eyes of 30 subjects in the SYMM group. Within the ASYMM group, best eye and worst eye were determined and all parameters were subtracted as worst eye minus best eye. Biomechanical metrics included corneal hysteresis (CH) from the Ocular Response Analyzer, and stiffness parameters at first applanation (SP-A1) and highest concavity (HC), as well as Integrated Inverse Radius and Deformation Amplitude Ratio, all from the Corvis ST. In addition, pulsatile ocular blood volume (POBV) was calculated based on intraocular pressure (IOP) and ocular pulse amplitude (OPA) from pneumatonometry and axial length. Paired T-test comparisons were performed between eyes of both ASYMM and SYMM groups for each variable. Statistical analyses was performed with SAS with the significance threshold set to p < 0.05.
Results :
Within ASYMM group, CH was significantly different by -0.76 (SD 1.22, p = 0.025) with the worst eye having lower CH. POBV was significantly different by -0.38 (SD 0.305, p = 0.016) with the worst eye having lower POBV. For SYMM there were no significantly different variables.
Conclusions :
Low CH is associated with greater glaucomatous damage between eyes in asymmetric glaucoma, which is consistent with literature reporting CH as a risk factor. In addition, this study showed that the eye with greater glaucomatous damage in asymmetric glaucoma was also associated with lower pulsatile ocular blood volume which may have contributed to the more severe disease.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.