Abstract
Purpose :
To analyze the impact of eye retraction on ocular structures deformations during air puff using full eye length SS-OCT data. To assess the impact of intraocular pressure on lens axial wobbling due to air-puff.
Methods :
Twenty Caucasian healthy subjects (mean age 27.6±3.5 yo) were recruited. The mean spherical equivalent refractive error was -1.1±1.5D, with a mean K_ave of 43.6±1.7D, and mean cylinder -0.93±0.67D. The measurements were performed on a single eye of each subject. The subjects underwent full ophthalmic examination including slit lamp biomicroscopy and corneal topography. A prototype long depth range SS-OCT operating at 1µm wavelength and at a sweep rate of 30,000 A-scans/s, was integrated with a non-contact tonometer to image the entire eye length during air puff stimulus. The OCT data consisting of 4000 A-scans were acquired along the visual axis (measurement time 133 ms). The intraocular pressure (IOP) was assessed using Goldmann tonometer prior to the OCT scanning. The data set carried information on the dynamics of all ocular elements during air-puff and allowed to extract the eye retraction and lens wobbling amplitudes (Fig.1). The effects of eye retraction and lens wobbling were modelled using rheological model.
Results :
Long-range SS-OCT along the visual axis enabled visualization of the eye dynamics during the air-puff stimulation with high temporal resolution. Significant statistical differences were found in corneal deformation amplitude (no correction=1.10±0.09mm; eye-retraction correction=0.89±0.23mm, p-value=0.0005), oscillatory lens wobbling amplitude (no correction=0.25±0.04mm; eye-retraction correction=0.10±0.04mm, p-value=0.0001) and corneal hysteresis (no correction=0.038±0.007µJ, eye-retraction correction=0.013±0.003µJ, p-value=0) when eye retraction correction was applied. This allowed also to obtain statistically significant correlation of those parameters with the IOP. Rheological model could characterize the observed effects (Fig.2).
Conclusions :
Air-puff long-range SS-OCT allows determination of the eye retraction and correct time-dependent deformation profiles of all ocular structures. This provides access to axial lens wobbling effect, which is correlated with the IOP.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.