Correction of refractive distortion in whole‐eye optical coherence tomography imaging of the mouse eye

Abstract

Optical coherence tomography (OCT) is an imaging modality that acquires high‐resolution cross‐sectional images of living tissues and it has become the standard in ophthalmological diagnoses. However, most quantitative morphological measurements are based on the raw OCT images which are distorted by several mechanisms such as the refraction of probe light in the sample and the scan geometries and thus the analysis of the raw OCT images inevitably induced calculation errors. In this paper, based on Fermat's principle and the concept of inverse light tracing, image distortions due to refraction occurred at tissue boundaries in the whole‐eye OCT imaging of mouse by telecentric scanning were corrected. Specially, the mathematical correction models were deducted for each interface, and the high‐precision whole‐eye image was recovered segment by segment. We conducted phantom and in vivo experiments on mouse and human eyes to verify the distortion correction algorithm, and several parameters of the radius of curvature, thickness of tissues and error, were calculated to quantitatively evaluate the images. Experimental results demonstrated that the method can provide accurate and reliable measurements of whole‐eye parameters and thus be a valuable tool for the research and clinical diagnosis.

Time-Serial Evaluation of the Development and Treatment of Myopia in Mice Eyes Using OCT and ZEMAX

“…Recently, we proposed a segment-by-segment optical correction method for whole-eye OCT imaging which reduced the image errors accumulating over the depth in a stack of different layers of eye tissues. The accuracy of this mathematical correction model was verified in experiments on ex vivo phantom and in vivo experiments of mouse and human eyes [15]. Based on the whole-eye corrected OCT images, in this study, we accurately measured the biological structure parameters of the mice eyes to study the morphological change in the process of myopia.…”

“…Our recent study presented a systematic segment-by-segment correction method to realize light-distortion correction from cornea to retina without any boundary fitting. Comparative experiments with other optical correction methods on mice and human eyes demonstrated the highest accuracy of the proposed method to recover OCT images to their real physical scale [13][14][15].…”

“…Continuing to repeat the above calculation steps, the light path in all intraocular tissues was corrected for each boundary. Details can be seen in reference [15]. In the correction process, the refractive index parameters at 840 nm incident beam used for eye tissues were: cornea 1.4015, aqueous humor 1.3336, lens 1.557, and vitreous 1.3329 [33][34][35][36], respectively.…”