Novel Parameters to Assess the Severity of Corneal Neovascularization Using Anterior Segment Optical Coherence Tomography Angiography

Binotti, William; Koseoglu, Neslihan Dilruba; Nosé, Ricardo Menon; Kenyon, Kenneth R.; Hamrah, Pedram

doi:10.1016/j.ajo.2020.08.023

Cited by 7 publications

(3 citation statements)

References 47 publications

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“…The application of OCTA to investigate vessel morphology has been demonstrated for monitoring inflammation 38 , corneal neovascularization 39 , 40 , limbal stem cell deficiency 41 , and tumor growth 42 . Thus, anterior eye OCTA may serve as a non-invasive alternative to fluorescein angiography for assessing vascular morphology to determine malignancy.…”

Section: Discussionmentioning

confidence: 99%

High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

Chen

Potsaid

et al. 2022

Sci Rep

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This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but also enables volumetric OCT for comprehensive structural analysis and OCT angiography (OCTA) for visualizing vasculature. The 15.5 mm (~ 11.6 mm in tissue) depth range spans all optical surfaces from the anterior cornea to the posterior lens capsule. The 1310 nm wavelength range enables structural OCT and OCTA deep in the sclera and through the iris. Achieving high speed and long range requires linearizing the VCSEL wavenumber sweep to efficiently utilize analog-to-digital conversion bandwidth. Dual channel recording of the OCT and calibration interferometer fringe signals, as well as sweep to sweep wavenumber compensation, is used to achieve invariant 12.2 µm (~ 9.1 µm in tissue) axial resolution and optimum point spread function throughout the depth range. Dynamic focusing using a tunable liquid lens extends the effective depth of field while preserving the lateral resolution. Improved optical and mechanical design, including parallax “split view” iris cameras and stable, ergonomic patient interface, facilitates accurate instrument positioning, reduces patient motion, and leads to improved imaging data yield and measurement accuracy. We present structural and angiographic OCT images of the anterior eye, demonstrating the unique imaging capabilities using representative scanning protocols which may be relevant to future research and clinical applications.

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Section: Discussionmentioning

confidence: 99%

High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

Chen

Potsaid

et al. 2022

Sci Rep

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“…A top hat filter has been frequently proposed as a method to reduce noise and remove small particles in the image without distortion. 32 , 43 Although the combination of a top hat filter with a bandpass filter is the most commonly performed, 33 , 43 , 46 , 47 we further explored the impact each filter on the VD agreement. In this study, an isolated top hat filter followed by a local threshold method showed worse agreement compared to the combined top hat and bandpass filters ( Table 2 ).…”

Section: Discussionmentioning

confidence: 99%

Automated Image Threshold Method Comparison for Conjunctival Vessel Quantification on Optical Coherence Tomography Angiography

Binotti

Saukkonen

Seyed‐Razavi

et al. 2022

Trans. Vis. Sci. Tech.

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Purpose To determine the impact of image binarization and the best thresholding method for conjunctival optical coherence tomography angiography (OCTA). Methods Vessel density (VD) of 14 OCTA conjunctival images (nine nasal and five temporal conjunctivas, and eight right and six left eyes) from normal subjects was analyzed. The binarization of gold-standard images, created by removing pixels that do not represent vessels on ImageJ software, was assessed by three masked graders to determine consistency of VD for images. Various thresholding methods on ImageJ, including manual, 1-, 2- and 3-step processes, were performed on unprocessed images for comparison. Interclass correlation coefficient (ICC) ≥0.750 were classified as good reliability and selected for calculation of the performance of the pixel location in the binarized images of each method. Results Analysis of the gold-standard threshold method achieved an ICC of 0.816 with excellent agreement ( R 2 = 0.965, P < 0.001). From a total 28 different methods and variations performed, only nine methods performed with good reliability, including two 1-step thresholds, six 2-step thresholds, and one 3-step threshold method. Overall, 2-step threshold methods were more reliable than 3-step threshold methods. The 2-step method of Bandpass filter + Phansalkar local threshold (LT) showed the best performance with mean pixel accuracy of 86.9% ± 6.8%, area under the curve of 0.826, sensitivity of 79.0%, and specificity 86.1%. Conclusions Bandpass filter + Phansalkar LT was the best method for VD measurement in conjunctival OCTA. Most commonly reported threshold methods showed unsatisfactory agreement. There is a need in the OCTA field for a standardized method to allow comparison between different studies. Translational Relevance The proposed threshold method using a widely accessible and commonly used software provides an accurate VD measurement for future OCTA studies.

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“…OCTA allows simultaneous evaluation of the lesion structure and its related vessels in three-dimensions and at any predetermined depth ( 24 ). Severe corneal neovascularization (CoNV) always presents thicker, deeper, larger vessels on AS-OCTA ( 51 ). It has been noted that the extension and thickness of CoNV is related to the severity of limbal stem cell deficiency (LSCD) and best corrected visual acuity (BCVA) ( 52 ).…”

Section: As-octa Precise Diagnosismentioning

confidence: 99%

Advances and Current Clinical Applications of Anterior Segment Optical Coherence Tomography Angiography

Luo

Zhuo

2021

Front. Med.

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Optical coherence tomography angiography (OCTA) is the most relevant evolution based on optical coherence tomography (OCT). OCTA can present ocular vasculature, show detailed morphology for assessment, and quantify vessel parameters without intravenous dye agent. Research on the anterior segment OCTA (AS-OCTA) is only in its initial phase, and its advances in clinical diagnosis and treatment efficacy evaluations require a detailed comparison to traditional imaging methods. In this review of AS-OCTA, we summarize its technical features, imaging advances, current clinical applications in various eye diseases, as well as its limitations and potential future directions. AS-OCTA offers potential advantages in ophthalmic imaging, and with further development it could become a common tool in the near future.

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Novel Parameters to Assess the Severity of Corneal Neovascularization Using Anterior Segment Optical Coherence Tomography Angiography

Cited by 7 publications

References 47 publications

High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

Automated Image Threshold Method Comparison for Conjunctival Vessel Quantification on Optical Coherence Tomography Angiography

Advances and Current Clinical Applications of Anterior Segment Optical Coherence Tomography Angiography

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