Imaging and full-length biometry of the eye during accommodation using spectral domain OCT with an optical switch

Abstract

An optical switch was implemented in the reference arm of an extended depth SD-OCT system to sequentially acquire OCT images at different depths into the eye ranging from the cornea to the retina. A custom-made accommodation module was coupled with the delivery of the OCT system to provide controlled step stimuli of accommodation and disaccommodation that preserve ocular alignment. The changes in the lens shape were imaged and ocular distances were dynamically measured during accommodation and disaccommodation. The system is capable of dynamic in vivo imaging of the entire anterior segment and eye-length measurement during accommodation in real-time.

Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging

“…1(C)) for imaging the ciliary muscle and the anterior segment, respectively. Details about the individual OCT systems were previously reported [28,29]. Briefly, imaging at 840 nm of the eye ranging from the cornea to the lens along the horizontal plane is achieved by stitching two OCT frames consecutively acquired at different depths using a high-speed optical switch implemented in the reference arm.…”

“…1(B)). A dichroic mirror was used to optically couple the NIR light of the AS-OCT delivery system with the visible light produced by the accommodation unit [28]. The accommodation module consists of two optical channels, each based on a variation of the Badal optometer, that were combined to produce a monocular accommodation step stimulus while minimizing ocular convergence during the imaging procedure [28].…”

“…A dichroic mirror was used to optically couple the NIR light of the AS-OCT delivery system with the visible light produced by the accommodation unit [28]. The accommodation module consists of two optical channels, each based on a variation of the Badal optometer, that were combined to produce a monocular accommodation step stimulus while minimizing ocular convergence during the imaging procedure [28]. The OCT probe of the AS-OCT system is mechanically coupled to the accommodation module so that it can be rotated and translated to allow precise alignment of the anterior segment OCT image plane with the optical axis of the eye while the subject fixates on the visible target.…”

“…We previously described an extended depth SD-OCT system operating at a central wavelength of 840nm that enabled 2D imaging and full-length ocular biometry during dynamic accommodation [28]. We also recently demonstrated high-resolution live and 3D imaging and biometry of the ciliary muscle during dynamic accommodation using a transscleral SD-OCT system operating at a central wavelength of 1325 nm [29].…”

Changes in anterior chamber eye during accommodation as assessed using a Dual Scheimpflug system

“…24 SD= standard deviation; AC-OCT= anterior chamber optical coherence tomography; AC= anterior chamber; UBM= ultrasound biomicroscopy; UL-OCT= ultralong scan depth optical coherence tomography; MRI= magnetic resonance imaging; HR-OCT= high-resolution optical coherence tomography; AS-OCT= anterior segment optical coherence tomography; SD-OCT= Spectral domain optical coherence tomography; SL-OCT= Slit lamp optical coherence tomography; PCI= Partial coherence interferometry. no previous studies assessed the possible changes in ACA during accommodation in young population.…”