Purchase this article with an account.
Félix Lalonde, Luke Beaton, Maribel Hidalgo, Denise Descovich, Mark Lesk, Santiago Costantino; Reproducibility of non-invasive measurement of choroidal volume change and ocular rigidity through automated segmentation of high-speed OCT imaging. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6144.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The exact pathophysiology of open-angle glaucoma (OAG) remains to be fully understood. One hypothesis is that ocular rigidity (OR) might play a role in this disease. Our goal is to develop a non-invasive method to measure OR. Our approach is based on the Friedenwald Equation: we determine pulsatile ocular volume change using a modified video-rate Spectral Domain Optical Coherence Tomomograph (OCT) and ocular pulse amplitude (OPA) using Dynamic Contour Tonometry (DCT). We computed the OR coefficient from these parameters. We then tested the reproducibility of this technique for choroidal thickness (CT), change in choroidal thickness (∆CT), ocular volume change (∆V), OPA and OR.
15 subjects (6 normals, 5 OAG, 2 OAG Suspects, 1 early OAG and 1 subject with a trabeculectomy) had repeated measures approximately 5 minutes apart. First, we acquired the video with the OCT and immediately after took the IOP/OPA measurements with the DCT. Axial length was also acquired using a Zeiss IOLMaster between the two series. We analyzed the OCT images with a automated MATLAB segmentation algorithm (see Beaton et al, ARVO 2015) which gives us CT, ∆CT, ∆V and OR. We then calculated the intraclass correlation coefficient (ICC) with bootstrap 95% confidence interval (CI).
The ICC of OR was 0,948 (95% CI: 0,843-0,982). The ICC of ∆V was 0,608 (95% CI: -0,063-0,864). The ICC of OPA was 0,981 (95% CI: 0,944-0,993). The ICC of CT was 0,825 (95% CI: 0,471-0,942). The ICC of ∆CT was 0,594 (95% CI: -0,206-0,863).
The OR values we obtained have good reproducibility. This new technique may help us better understand the biomechanical basis of ocular disease. Further studies will be needed to better characterize different diseases.
This PDF is available to Subscribers Only