Abstract
Purpose :
To measure the distortion-corrected retinal curvature with a ultrawide-field OCT system using an ultrafast Fourier domain mode locking (FDML) laser.
Methods :
An ultrafast swept-source OCT system (OptoRes, Germany) using a 1.6MHz FDML laser (central wavelength: 1060nm) was used for dense imaging of an ultrawide field of view (FOV, ~65 degree) of the posterior eye. The imaging FOV was calibrated with a custom-built phantom eye. A total of 13 eyes from 11 healthy volunteers, with spherical equivalent (SE) refraction from -1D to -7D, and axial length (AL) from 23.1 mm to 26.8 mm, were imaged thrice without mydriasis. Retinal pigment epithelium (RPE) was segmented automatically using MATLAB. Ocular biometrics, including AL, central corneal thickness and corneal curvature were acquired with the IOL Master700. Ocular biometrics and system parameters were fed into a ray tracing algorithm using ZEMAX and MATLAB, for correction of the optical and display distortions and mapping the RPE segmentation into spatial location. The radius of curvature (Rc) of the retina was calculated by finding the best sphere fit to the corrected RPE.
Results :
The mean ± standard deviation (SD) of Rc in 13 eyes was 12.86 ± 0.19 mm. A high repeatability was obtained for Rc measurements (intraclass correlation coefficient, ICC = 0.96). Rc was correlated with the AL (r = -0.389), but not correlated with the SE (r = -0.015) (Figure 1). Figure 2 shows the original RPE elevation maps and their corrected retinal shapes in eyes with mild (SE=-2.25D) and moderate (SE=-4.25D) myopia.
Conclusions :
The distortion-corrected measurements of Rc using an ultra-fast widefield OCT can provide the true retinal curvature with high repeatability. This suggests that wide-field OCT may be used to monitor retinal curvature changes in myopia over time.
This is a 2021 ARVO Annual Meeting abstract.