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Limited visualization of semi-transparent structures in the eye remains a critical barrier to improving clinical outcomes and developing novel surgical techniques. While increases in imaging speed has enabled intraoperative optical coherence tomography (iOCT) imaging of surgical dynamics, several critical barriers to clinical adoption remain. Our previous implementation of surgical microscope-integrated multimodal imaging technologies to address these limitations lacked the resolution and optical throughput for in vivo retinal imaging. Here, we present an optimized intraoperative spectrally encoded coherence tomography and reflectometry (iSECTR) system and demonstrate in vivo multimodality ophthalmic imaging.
The ophthalmic surgical microscope objective was optically characterized to develop a lens model for system design. We estimated the glass thicknesses, refractive index, and intermediate curvature of the doublet objective lens using a novel combination of OCT, focus tracking, and computational ray tracing. The resulting lens model and corresponding optical aberrations were used to optimize the optical design for an iSECTR scan-head. In vivo ophthalmic imaging using iSECTR was performed on a healthy volunteer. En face spectrally encoded reflectometry (SER) and cross-sectional OCT images were acquired at 350 fps with 2560 x 1000 pix. (spectral x lateral). OCT volumes of 1000 B-scans were acquired in 2.86 s. Retinal and choroidal vasculature were readily visible on SER and provided complementary contrast to the OCT volume projection. We presented optimized designs for multimodal ophthalmic imaging with surgical microscope-integrated iSECTR. Clinical translation of iSECTR will benefit real-time instrument and FOV tracking for imaging of surgical dynamics and image-guided ophthalmic surgery.
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