Comparison of Measurements Obtained With High-Speed Anterior Segment Swept Source Optical Coherence Tomography and an Optical Device for Measuring Axial Length in Healthy Eyes

A high-speed, high-resolution swept-source optical coherence tomography (SS-OCT) is presented for focusing lens imaging and a k-domain uniform algorithm is adopted to find the wave number phase equalization. The radius of curvature of the laser focusing lens was obtained using a curve-fitting algorithm. The experimental results demonstrate that the measuring accuracy of the proposed SS-OCT system is higher than the laser confocal microscope. The SS-OCT system has great potential for surface topography measurement and defect inspection of the focusing lens.

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Objective quantification of lens nuclear opacities using swept-source anterior segment optical coherence tomography

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-318334 ◽

2021 ◽

pp. bjophthalmol-2020-318334

Author(s):

Wei Wang ◽

Jiaqing Zhang ◽

Xiaoxun Gu ◽

Xiaoting Ruan ◽

Xiaoyun Chen ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Visual Acuity ◽

Anterior Segment ◽

Training Dataset ◽

Dissipated Energy ◽

Nuclear Density ◽

Optical Coherence ◽

Nuclear Cataract ◽

Swept Source ◽

Ultrasonic Time

Background/aimsThe primary objective is to quantify the lens nuclear opacity using swept-source anterior segment optical coherence tomography (SS-ASOCT) and to evaluate its correlations with Lens Opacities Classification System III (LOCS-III) system and surgical parameters. The secondary objective is to assess the diagnostic performance for hard nuclear cataract.MethodsThis cross-sectional study included 1222 patients eligible for cataract surgery (1222 eyes). The latest SS-ASOCT (CASIA-2) was used to obtain high-resolution lens images, and the average nuclear density (AND) and maximum nuclear density (MND) were measured by a custom ImageJ software. Spearman’s correlations analysis was used to assess associations of AND/MND with LOCS-III nuclear scores, visual acuity and surgical parameters. The subjects were then split randomly (9:1) into the training dataset and validating dataset. Receiver operating characteristic curves and calibration curves were constructed for the classification on hard nuclear cataract.ResultsThe AND and MND from SS-ASOCT images were significantly correlated with nuclear colour scores (AND: r=0.716; MND: r=0.660; p<0.001) and nuclear opalescence scores (AND: r=0.712; MND: r=0.655; p<0.001). The AND by SS-ASOCT images had the highest values of Spearman’s r for preoperative corrected distance visual acuity (r=0.3131), total ultrasonic time (r=0.3481) and cumulative dissipated energy (r=0.4265). The nuclear density had good performance in classifying hard nuclear cataract, with area under the curves of 0.859 (0.831–0.886) for AND and 0.796 (0.768–0.823) for MND.ConclusionObjective and quantitative evaluation of the lens nuclear density using SS-ASOCT images enable accurate diagnosis of hard nuclear cataract.

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Relevance of Swept-Source Anterior Segment Optical Coherence Tomography for Corneal Imaging in Patients With Flap-Related Complications After LASIK

Cornea ◽

10.1097/ico.0000000000001773 ◽

2019 ◽

Vol 38 (1) ◽

pp. 93-97 ◽

Cited By ~ 5

Author(s):

Khaled Abdelazeem ◽

Mohamed Sharaf ◽

Mohamed G. A. Saleh ◽

Ahmed M. Fathalla ◽

Wael Soliman

Keyword(s):

Optical Coherence Tomography ◽

Anterior Segment ◽

Optical Coherence ◽

Swept Source ◽

Corneal Imaging

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Optical Coherence Tomography as a Tool for Ocular Dynamics Estimation

BioMed Research International ◽

10.1155/2015/293693 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Damian Siedlecki ◽

Waldemar Kowalik ◽

Henryk Kasprzak

Keyword(s):

Heart Rate ◽

Optical Coherence Tomography ◽

Spectral Analysis ◽

High Speed ◽

Anterior Segment ◽

Power Spectra ◽

Optical Coherence ◽

Tomographic Images ◽

Noninvasive Estimation ◽

Ocular Hemodynamics

Purpose. The aim of the study is to demonstrate that the ocular dynamics of the anterior chamber of the eye can be estimated quantitatively by means of optical coherence tomography (OCT).Methods. A commercial high speed, high resolution optical coherence tomographer was used. The sequences of tomographic images of the iridocorneal angle of three subjects were captured and each image from the sequence was processed in MATLAB environment in order to detect and identify the contours of the cornea and iris. The data on pulsatile displacements of the cornea and iris and the changes of the depth of the gap between them were retrieved from the sequences. Finally, the spectral analysis of the changes of these parameters was performed.Results. The results of the temporal and spectral analysis manifest the ocular microfluctuation that might be associated with breathing (manifested by 0.25 Hz peak in the power spectra), heart rate (1–1.5 Hz peak), and ocular hemodynamics (3.75–4.5 Hz peak).Conclusions. This paper shows that the optical coherence tomography can be used as a tool for noninvasive estimation of the ocular dynamics of the anterior segment of the eye, but its usability in diagnostics of the ocular hemodynamics needs further investigations.

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Morphometric measurement of Schlemm’s canal in normal human eye using anterior segment swept source optical coherence tomography

Journal of Biomedical Optics ◽

10.1117/1.jbo.17.1.016016 ◽

2012 ◽

Vol 17 (1) ◽

pp. 016016 ◽

Cited By ~ 14

Author(s):

Guohua Shi

Keyword(s):

Optical Coherence Tomography ◽

Anterior Segment ◽

Optical Coherence ◽

Morphometric Measurement ◽

Schlemm’S Canal ◽

Swept Source ◽

Human Eye ◽

Schlemm's Canal ◽

Normal Human

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The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

Indian Journal of Ophthalmology ◽

10.4103/ijo.ijo_936_20 ◽

2021 ◽

Vol 69 (4) ◽

pp. 865

Author(s):

Xiulan Zhang ◽

Wenbin Huang ◽

Xingyi Li ◽

Xinbo Gao

Keyword(s):

Optical Coherence Tomography ◽

Anterior Segment ◽

Angle Closure ◽

Optical Coherence ◽

Swept Source ◽

Primary Angle Closure

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Age-Related Changes in the Rhesus Macaque Eye

10.1101/2021.07.14.452427 ◽

2021 ◽

Author(s):

Kira Lin ◽

Tu Tran ◽

Soohyun Kim ◽

Sangwan Park ◽

Jiajia Chen ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Intraocular Pressure ◽

Rhesus Macaque ◽

Axial Length ◽

Rhesus Macaques ◽

Anterior Segment ◽

Optical Coherence ◽

Lens Thickness ◽

Age Related ◽

Age Related Changes

Purpose: To assess age-related changes in the rhesus macaque eye and evaluate them to corresponding human age-related eye disease. Methods: Data from eye exams and imaging tests including intraocular pressure (IOP), lens thickness, axial length, and retinal optical coherence tomography (OCT) images were evaluated from 142 individuals and statistically analyzed for age-related changes. Quantitative autofluorescence (qAF) was measured as was the presence of macular lesions as related to age. Results: Ages of the 142 rhesus macaques ranged from 0.7 to 29 years (mean=16.4 years, stdev=7.5 years). Anterior segment measurements such as IOP, lens thickness, and axial length were acquired. Advanced retinal imaging in the form of optical coherence tomography and qAF were obtained. Quantitative assessments were made and variations by age groups were analyzed to compare with established age-related changes in human eyes. Quantitative analysis of data revealed age-related increase in intraocular pressure, ocular biometry (lens thickness and axial length), and presence of macular lesions. Age-related changes in thicknesses of retinal layers on OCT were observed and quantified. Age was correlated with increased qAF. Conclusions: The rhesus macaque has age-related ocular changes similar to humans. IOP increases with age while retinal ganglion cell layer thickness decreases. Macular lesions develop in some aged animals. Our findings support the concept that rhesus macaques may be useful for the study of important age-related diseases such as glaucoma, macular diseases, and cone disorders, and for development of therapies for these diseases.

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Wide-field optical coherence tomography deviation map for early glaucoma detection

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2021-319509 ◽

2021 ◽

pp. bjophthalmol-2021-319509

Author(s):

Hyungjun Kim ◽

Hae Min Park ◽

Hyo Chan Jeong ◽

So Yeon Moon ◽

Hyunsoo Cho ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Characteristic Curve ◽

Wide Field ◽

Optical Coherence ◽

Diagnostic Ability ◽

Swept Source ◽

Early Glaucoma ◽

Field Database ◽

The Individual ◽

Healthy Eyes

Background/aimsThis study aimed to establish a wide-field optical coherence tomography (OCT) deviation map obtained from swept-source OCT (SS-OCT) scans. Moreover, it also aimed to compare the diagnostic ability of this wide-field deviation map with that of the peripapillary and macular deviation maps currently being used for the detection of early glaucoma (EG).MethodsFour hundred eyes, including 200 healthy eyes and 200 eyes with EG were enrolled in this retrospective observational study. Patients underwent a comprehensive ocular examination, including wide-field SS-OCT (DRI-OCT Triton; Topcon, Tokyo, Japan). The individual wide-field scan was converted into a uniform template using the fovea and optic disc centres as fixed landmarks. Subsequently, the wide-field deviation map was obtained via the comparison between individual wide-field data and a normative wide-field database that had been created by combining images of healthy eyes into a uniform template in a previous study. The ability of the new wide-field deviation map to distinguish between EG and healthy eyes was assessed by comparing it with conventional deviation maps based on the area under the receiver operating characteristic curve (AUC).ResultsThe wide-field deviation map obtained using the normative wide-field database showed the highest diagnostic ability for the diagnosis of EG (AUC=0.980 and 961 for colour-coded pixels presenting <5% and <1%, respectively) among various deviation maps. Its AUC was significantly superior to that of most conventional deviation maps (p<0.05). The wide-field deviation map demonstrated early structural glaucomatous damage well over a wider area.ConclusionThe wide-field SS-OCT deviation map exhibited good performance for distinguishing between eyes with EG and healthy eyes. The visualisation of the wider damaged area on the wide-field deviation map could be useful for the diagnosis of EG in clinical settings.

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