Distributed scanning volumetric SDOCT for motion corrected corneal biometry

McNabb, Ryan P.; Larocca, Francesco; Farsiu, Sina; Kuo, Anthony N.; Izatt, Joseph A.

doi:10.1364/boe.3.002050

Cited by 30 publications

(35 citation statements)

References 37 publications

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“…To reduce the effects of patient motion during acquisition, we utilized a technique we previously developed termed distributed scanning OCT (DSOCT). 23 DSOCT uses a custom scanning protocol applied on a commercial spectral domain OCT instrument that reduces the temporal correlation between adjacent A-scans and allows for motion estimation and removal of patient bulk motion that occurs during volume acquisition. Using DSOCT, we previously found that differences in corneal power measurements between OCT and standard keratometric techniques were reduced over no motion correction in normal eyes, 23, 24 Figure 1 illustrates the DSOCT technique.…”

Section: Methodsmentioning

confidence: 99%

Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

et al. 2015

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Purpose To determine the ability of motion corrected optical coherence tomography (OCT) to measure the corneal refractive power change due to laser in situ keratomileusis (LASIK). Design Evaluation of a diagnostic test or technology in a cohort. Subjects 70 eyes from 37 subjects undergoing LASIK were measured preoperatively. 39 eyes from 22 subjects were measured postoperatively and completed the study. Methods Consecutive patients undergoing LASIK at the Duke Eye Center who consented to participate were imaged with Placido-ring topography, Scheimpflug photography and OCT on the day of their surgery. Patients were then reimaged with the same imaging systems at the post-operative month 3 visit. Change in pre- to post-operative corneal refractive power as measured by each of the imaging modalities was compared to the pre- to post-operative change in manifest refraction using t-test with generalized estimating equations. Main Outcome Measures Corneal refractive power change due to LASIK as measured by Placido-ring topography, Scheimpflug Photography, and OCT compared to the manifest refraction change vertexed to the corneal plane. The change in manifest refraction should correspond to the change in the corneal refractive power from LASIK and was considered the reference measurement. Results In 22 returning post-LASIK individuals (39 eyes), we found no significant difference between the clinically measured pre to post LASIK change in manifest refraction and both Scheimpflug photography (p = 0.714) and OCT (p = 0.216). In contrast, keratometry values from Placido-ring topography were found to be significantly different from the measured refractive change (p < 0.001). Additionally, of the three imaging modalities, OCT recorded the smallest mean absolute difference from the reference measurement with the least amount of variability. Conclusion Motion corrected OCT more accurately measures the change in corneal refractive power due to laser refractive surgery than currently available clinical devices. By offering accurate corneal refractive power measurements in normal and surgically modified subjects, OCT offers a compelling alternative to current clinical devices for determining corneal refractive power.

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Section: Methodsmentioning

confidence: 99%

Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

et al. 2015

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“…[11][12][13][14] A tradeoff always exists between fast image acquisition and high image quality, and if the image acquisition speed is increased, then SNR will suffer. [7,10] OCT scanners laterally sample a target by steering the beam across one or two dimensions in order to produce a 2D image or a 3D volume. Processing the samples from the target to create an image is also a computationally intensive task, and the total time it takes to process the samples into an image can be higher than the line scan acquisition rate.…”

Section: Introductionmentioning

confidence: 99%

Graphics Processor Unit (GPU) Accelerated Shallow Transparent Layer Detection in Optical Coherence Tomographic (OCT) Images for Real-Time Corneal Surgical Guidance

Mathai

Galeotti

Horvath

et al. 2014

Augmented Environments for Computer-Assisted Interventions

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Abstract. An image analysis algorithm is described that utilizes a Graphics Processor Unit (GPU) to detect in real-time the most shallow subsurface tissue layer present in an OCT image obtained by a prototype SDOCT corneal imaging system. The system has a scanning depth range of 6mm and can acquire 15 volumes per second at the cost of lower resolution and signal-to-noise ratio (SNR) than diagnostic OCT scanners. To the best of our knowledge, we are the first to experiment with non-median percentile filtering for simultaneous noise reduction and feature enhancement in OCT images, and we believe we are the first to implement any form of non-median percentile filtering on a GPU. The algorithm was applied to five different test images. On an average, it took ~0.5 milliseconds to preprocess an image with a 20 th -percentile filter, and ~1.7 milliseconds for our second-stage algorithm to detect the faintly imaged transparent surface.

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“…Depending on the sample and motion characteristic, different concepts for motion compensation either during image acquisition or by means of image postprocessing have been published for OCT applications. Methods used during image acquisition include increasing the imaging speed to reduce acquisition time [11], triggering acquisition by synchronization of OCT data with an independent measurement of the phase of the respiratory cycle [15], and adapting the scanning scheme to the individual application [16]. In accordance with recent publications [13], we observed that the effect of motion artifacts is significantly smaller in single brightness scans (B-scans) (fast scanning axis) than in subsequent B-scans forming classic three-dimensional (3D) stacks.…”

Section: Introductionmentioning

confidence: 99%

In situ optical coherence tomography of percutaneous implant-tissue interfaces in a murine model

Donner¹,

Müller

Witte

et al. 2013

Biomedizinische Technik/Biomedical Engineering

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Novel surface coatings of percutaneous implants need to be tested in biocompatibility studies. The use of animal models for testing usually involves numerous lethal biopsies for the analysis of the implant-tissue interface. In this study, optical coherence tomo graphy (OCT) was used to monitor the reaction of the skin to a percutaneous implant in an animal model of hairless but immunocompetent mice. In vivo optical biopsies with OCT were taken at days 7 and 21 after implantation and post mortem on the day of noticeable inflammation. A Fourier-domain OCT was programmed for spoke pattern scanning schemes centered at the implant midpoint to reduce motion artifacts during in vivo imaging. Image segmentation allowed the automatic detection and morphometric analysis of the skin contour and the subcutaneous implant anchor. On the basis of the segmentation, the overall refractive index of the tissue within one OCT data set was estimated as a free parameter of a fitting algorithm, which corrects for the curved distortion of the planar implant base in the OCT images. OCT in combination with the spoke scanning scheme and image processing provided time-resolved three-dimensional optical biopsies around the implants to assess tissue morphology.Keywords: in vivo; motion artifacts; refractive index; scanning scheme; segmentation. To the time point of the study, affiliated with Biomedical Optics Department, Laser Zentrum Hannover e.V., D-30419 Hannover, Germany and also with CrossBIT, Hannover Medical School, 30625 Hannover, Germany.

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Distributed scanning volumetric SDOCT for motion corrected corneal biometry

Cited by 30 publications

References 37 publications

Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

Graphics Processor Unit (GPU) Accelerated Shallow Transparent Layer Detection in Optical Coherence Tomographic (OCT) Images for Real-Time Corneal Surgical Guidance

In situ optical coherence tomography of percutaneous implant-tissue interfaces in a murine model

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