Abstract
Purpose :
Our purpose was to use dynamic optical coherence tomography (OCT) video to estimate ocular rigidity. Furthermore, we evaluated the relationship between ocular rigidity and the biomechanical and biometry characteristics of the human eye.
Methods :
Ocular rigidity was calculated using Friedenwald's empirical equation which estimates the change in intraocular pressure (IOP) produced by volumetric changes of the eye due to choroidal pulsations with each heartbeat. High-speed OCT video was utilized to noninvasively measure changes in choroidal volume through time-series analysis. A control-case study design was based on 23 healthy controls and 6 glaucoma cases. Multiple diagnostic modalities were performed during the same visit including Spectralis OCT for nerve head video, Pascal Dynamic Contour Tonometry for IOP and ocular pulse amplitude (OPA) measurement, Corvis ST for measuring dynamic biomechanical response, and Pentacam for characterizing biometry dimensions of the eye.
Results :
Ocular rigidity in glaucoma was significantly larger than in healthy eyes (p=0.039). Negative correlations of ocular rigidity were found with axial length (n=29, p=0.003), and anterior chamber volume (p=0.0002). A stronger correlation of ocular rigidity was observed with the stiffness parameter at the highest concavity (SP-HC; R=0.62, p=0.0005) quantifying scleral stiffness, than at the first applanation (SP-A1; R=0.41, p=0.033) quantifying corneal stiffness. In addition, there was a positive correlation between the ocular rigidity and the static pressure-volume ratio (P/V ratio) (p<0.0001) (see Fig.1).
Conclusions :
Ocular rigidity was noninvasively assessed using OCT video and OPA in a clinical setting. The strong correlation of ocular rigidity with biomechanical parameters, SP-HC and P/V ratio, demonstrated the validity of the ocular rigidity estimation. These in vivo methods offer an important approach to investigate the role of ocular biomechanics in glaucoma. Higher ocular rigidity in glaucoma offers evidence that the scleral stiffness is a contributing factor to the pathogenesis of glaucoma.
This is a 2021 ARVO Annual Meeting abstract.