Highly parallelized optical coherence tomography for ocular metrology and imaging

Anderson, Trevor; Segref, Armin; Frisken, Grant; Lorenser, Dirk; Ferrá, Herman L.; Frisken, Steve

doi:10.1117/12.2539905

Cited by 4 publications

(4 citation statements)

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“…Wagner et al [30] proposed a scan pattern based on Fermat's spiral in which the data is obtained in a distributed way allowing distorted parts of the scan to be excluded to reconstruct the full shape of the cornea even in the presence of severe eye movements, however the repeatability was not studied. Anderson et al [14] obtained data from different points of the cornea simultaneously using a multichannel acquisition OCT and reported a repeatability on the order of 0.1 D. Other scan types such as a spiral with isotropic transverse sampling [31], Lissajous curves [32] and orthogonal raster scan patterns [33] have been proposed for retinal imaging OCT, where features in the images can help to register the data with each other. Also, using a classical raster scan pattern there are methods to correct intra-volume motion correction algorithms [34], but to our knowledge, the applicability of these methods to calculate the topography of the cornea and the crystalline lens remains unexplored.…”

Section: Discussionmentioning

confidence: 99%

“…Scheimpflug photography has also the ability to image both the anterior and posterior corneal surfaces, but acquisition times are usually larger because of the mechanical movements needed to image the different meridians of the eye. Though multiplexing schemes using several beams simultaneously [12][13][14] and nonscanning techniques, such as line or full field OCT [15,16] have been described, in its most usual configuration, OCT uses a single beam that is scanned through the region of interest and the data is acquired sequentially. The two most common scan patterns employed to study the shape of the anterior segment 3D OCT are raster (where cross-sectional images, or B-scans, are stacked laterally) and radial scanning (where images are obtained from line radial scans, typically around a central corneal location).…”

Section: Introductionmentioning

confidence: 99%

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Effect of fixational eye movements in corneal topography measurements with optical coherence tomography

Castro¹,

Martinez-Enriquez²,

Marcos³

2023

Preprint

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There is an increasing interest in applying Optical Coherence Tomography (OCT) to quantify the topography of the ocular structures. However, in its most usual configuration, OCT data is acquired sequentially while a beam is scanned through the region of interest, and the presence of fixational eye movements can affect the accuracy of the technique. Several scan patterns and motion correction algorithms have been proposed to minimize this effect but there is no consensus on the ideal parameters to obtain a correct topography. We have acquired corneal OCT images, with raster and radial patterns, and modeled the data acquisition in the presence of eye movements. The simulations replicate the experimental variability in shape (radius of curvature and Zernike polynomials), corneal power, astigmatism, and calculated wavefront aberrations. The variability of the Zernike modes is highly dependent on the scan pattern, with higher variability in the direction of the slow scan axis. The model can be a useful tool to design motion correction algorithms and to determine the variability with different scan patterns.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of fixational eye movements in corneal topography measurements with optical coherence tomography

Castro¹,

Martinez-Enriquez²,

Marcos³

2023

Preprint

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“…The transverse scale of retinal images has been shown to be affected predominantly by axial length of the human eye. [62][63][64] The magnitude of this effect in small eyes is poorly understood, and future studies are warranted to assess the correlation between image scale derived by optical models (incorporating noninvasive measurements of ocular biometry, such as keratometry, 65 ultrasound, 66 partial coherence interferometry, 67 or whole-globe imaging with hyperparallel OCT 68 ) and empirical measurements using correlative histology 69 or application of exogenous agents with known size. 70 Intraperitoneal or intravenous injections of DiI or lectin-FITC immediately preceding euthanasia may also be effective and require less technical skill, but this was not explored here.…”

Section: Correlative Histologymentioning

confidence: 99%

Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel

Salmon

Chen

Atry

et al. 2021

Trans. Vis. Sci. Tech.

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To assess the performance of two spectral-domain optical coherence tomography-angiography systems in a natural model of hypoperfusion: the hibernating thirteen-lined ground squirrel (13-LGS).Methods: Using a high-speed (130 kHz) OCT-A system (HS-OCT-A) and a commercial OCT (36 kHz; Bioptigen Envisu; BE-OCT-A), we imaged the 13-LGS retina throughout its hibernation cycle. Custom software was used to extract the superior, middle, and deep capillary plexus (SCP, MCP, and DCP, respectively). The retinal vasculature was also imaged with adaptive optics scanning light ophthalmoscopy (AOSLO) during torpor to visualize individual blood cells. Finally, correlative histology with immunolabeled or DiIstained vasculature was performed.Results: During euthermia, vessel density was similar between devices for the SCP and MCP (P = 0.88, 0.72, respectively), with a small difference in the DCP (−1.63 ± 1.54%, P = 0.036). Apparent capillary dropout was observed during torpor, but recovered after forced arousal, and this effect was exaggerated in high-speed OCT-A imaging. Based on cell flux measurements with AOSLO, increasing OCT-A scan duration by ∼1000× would avoid the apparent capillary dropout artifact. High correspondence between OCT-A (during euthermia) and histology enabled lateral scale calibration. Conclusions:While the HS-OCT-A system provides a more efficient workflow, the shorter interscan interval may render it more susceptible to the apparent capillary dropout artifact. Disambiguation between capillary dropout and transient ischemia can have important implications in the management of retinal disease and warrants additional diagnostics.Translational Relevance: The 13-LGS provides a natural model of hypoperfusion that may prove valuable in modeling the utility of OCT-A in human pathologies associated with altered blood flow.

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“…The optical spot array can be generated through optical refraction or diffraction. In the refraction regime, the microlens array [10][11][12] has been widely used. Microlens array can be fabricated by thermal reflow [13,14], microplastic embossing [15,16], and ultrafast laser writing [17], etc.…”

Section: Introductionmentioning

confidence: 99%

Parametric Generation of Variable Spot Arrays Based on Multi-Level Phase Modulation

Zhang

Yang

et al. 2022

Photonics

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Holographic generation of beam spot array with high uniformity have been extensively investigated while existing methods cannot combine high quality and tunability. This paper demonstrated a method to generate beam spot array by using phase-only liquid crystal on silicon (LCOS) device. The proposed method is highly flexible and tolerant to the defects within the LCOS device. The uniformity deviation of the speckle array can be limited to within ±5% in the numerical simulation and the experimental results agreed well with the simulation results.

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Highly parallelized optical coherence tomography for ocular metrology and imaging

Cited by 4 publications

References 0 publications

Effect of fixational eye movements in corneal topography measurements with optical coherence tomography

Effect of fixational eye movements in corneal topography measurements with optical coherence tomography

Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel

Parametric Generation of Variable Spot Arrays Based on Multi-Level Phase Modulation

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