Reliability of Corneal, Epithelial, and Stromal Thickness Mapping for a 9-mm Zone Using Spectral-Domain Optical Coherence Tomography

Abstract Purpose To evaluate the reliability of spectral-domain optical coherence tomography (SD-OCT; RTVue XR; Optovue, Inc., Fremont, CA, USA) for thickness mapping of the entire cornea (CT), corneal epithelium (ET). and corneal stroma (ST) over a 9-mm zone in healthy eyes. We sought to develop reference values for different age groups and elucidate potential sex- and age-dependent characteristics of corneal sublayer pachymetry maps. Methods Three consecutive SD-OCT scans were obtained in 166 healthy right eyes (mean age = 50 ± 20 years). The thickness maps contain 25 sectors over a 9-mm diameter zone. To test measurement reliability, intraclass correlation coefficients (ICC), coefficients of variation (CoV), and within-subject standard deviations (WSSD) were calculated. Results CT, ET, and ST ICCs ranged from 0.961 to 0.998, 0.896 to 0.945, and 0.955 to 0.998, respectively. CoV values for CT, ET, and ST ranged between 0.3 and 1.5%, 1.6 and 4.2%, and 0.4 and 1.7%, respectively. WSSD ranged from 6 to 41, 4 to 8, and 7 to 46 µm, respectively. A negative correlation was found between age and ET (p < 0.05) but not between age and ST or CT. No gender-related differences in CT, ET, or ST were detected. CoV of CT, ET, and ST measurements showed a positive correlation with age in 28, 64, and 28% of the sectors, respectively. Conclusion SD-OCT is a rapid and noninvasive technique that provides excellent reliability for corneal sublayer thickness measurements over a 9-mm zone. The reliability of the ET measurement seems to be negatively affected by age. Peripheral CT and global ET thin with age.

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Measurement of Photoreceptor Layer in Glaucoma: A Spectral-Domain Optical Coherence Tomography Study

Journal of Ophthalmology ◽

10.1155/2011/264803 ◽

2011 ◽

Vol 2011 ◽

pp. 1-5 ◽

Cited By ~ 17

Author(s):

Ning Fan ◽

Nina Huang ◽

Dennis Shun Chiu Lam ◽

Christopher Kai-shun Leung

Keyword(s):

Optical Coherence Tomography ◽

Confidence Interval ◽

Outer Nuclear Layer ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Spectral Domain ◽

Optical Coherence ◽

Photoreceptor Layer ◽

Intraclass Correlation Coefficients ◽

Spectral Domain Oct

Objective.To measure and compare photoreceptor layer thickness between normal and glaucomatous eyes using spectral-domain optical coherence tomography (OCT).Methods. Thirty-eight healthy normal volunteers and 47 glaucoma patients were included in the analysis. One eye from each participant was randomly selected for macula imaging by a spectral-domain OCT (3D OCT-1000, Topcon, Tokyo, Japan). The foveal and parafoveal (1.5 mm from the fovea) outer nuclear layer (ONL) and inner and outer segments (IS+OS) layer thicknesses were measured by a single masked observer. The measurements were repeated 3 times in a random sample of 30 normal eyes to determine the repeatability coefficient and intraclass correlation coefficient.Results.The measurement variabilities of photoreceptor thickness were low. The respective intraclass correlation coefficients of ONL and IS+OS thicknesses were 0.96 (95% confidence interval: 0.94–0.98) and 0.82 (95% confidence interval 0.70–0.90). While there were no differences in parafoveal ONL and IS+OS thicknesses between normal and glaucoma groups (), the foveal ONL thickness was greater in glaucomatous eyes () than in normal eyes.Conclusions.Glaucomatous damage may involve structural change in the photoreceptor layer.

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Pre-, Intra-, and Post-Operative Evaluation of Extraocular Muscle Insertions Using Optical Coherence Tomography: A Comparison of Four Devices

Journal of Clinical Medicine ◽

10.3390/jcm8101732 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1732 ◽

Cited By ~ 2

Author(s):

Matthew S. Pihlblad ◽

Andrew Troia ◽

Sapna Tibrewal ◽

Parth R. Shah

Keyword(s):

Optical Coherence Tomography ◽

Intraclass Correlation ◽

Anterior Segment ◽

Correlation Coefficients ◽

Rectus Muscle ◽

Strabismus Surgery ◽

Optical Coherence ◽

Intraclass Correlation Coefficients ◽

Muscle Insertion ◽

Operative Evaluation

OCT (optical coherence tomography) is widely used in ophthalmology and pediatric ophthalmology, but limited research has been done on the use of OCT in strabismus. This study investigates the use of different OCT machines to image rectus muscle insertions pre-, intra-, and post-operatively in pediatric strabismus patients. The OCT machines used in the study were a Bioptigen (Leica Microsystems Inc., Buffalo Grove, IL, USA), Spectralis HRA+OCT with Anterior Segment Module (Heidelberg Engineering, Heidelberg, Germany), Visante (Carl Zeiss, Oberkochen, Germany), and Zeiss Rescan 700 (Carl Zeiss, Oberkochen, Germany). Measurements from the machines were compared with the caliper distance measured during the strabismus surgery before disinsertion or after reattachment. The OCT machines had moderate (Bioptigen: 0.62) to good intraclass correlation coefficients (Rescan: 0.83, Spectralis: 0.85, Visante: 0.88) with intra-operative measurements. To our knowledge, this is the first study to use an operating microscope with integrated intra-operative OCT to image rectus muscle insertions. OCT is a useful tool in strabismus surgical patients in the pre-, intra-, and post-operative settings, particularly in patients who have had previous surgery, when the muscle insertion is unknown. The ability to accurately image rectus muscle insertions has significant implications for the management of strabismus patients.

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Comparison of Methods for Estimating Retinal Shape: Peripheral Refraction vs. Optical Coherence Tomography

Journal of Clinical Medicine ◽

10.3390/jcm10020174 ◽

2021 ◽

Vol 10 (2) ◽

pp. 174

Author(s):

Katharina Breher ◽

Alejandro Calabuig ◽

Laura Kühlewein ◽

Focke Ziemssen ◽

Arne Ohlendorf ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Axial Length ◽

Pearson Correlation ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Clinical Parameter ◽

Mean Difference ◽

Optical Coherence ◽

Shape Estimation ◽

Intraclass Correlation Coefficients

Retinal shape presents a clinical parameter of interest for myopia, and has commonly been inferred indirectly from peripheral refraction (PRX) profiles. Distortion-corrected optical coherence tomography (OCT) scans offer a new and direct possibility for retinal shape estimation. The current study compared retinal curvatures derived from OCT scans vs. PRX measurements in three refractive profiles (0° and 90° meridians, plus spherical equivalent) for 25 participants via Bland–Altman analysis. The radial differences between both procedures were correlated to axial length using Pearson correlation. In general, PRX- and OCT-based retinal radii showed low correlation (all intraclass correlation coefficients < 0.21). PRX found flatter retinal curvatures compared to OCT, with the highest absolute agreement found with the 90° meridian (mean difference +0.08 mm) and lowest in the 0° meridian (mean difference +0.89 mm). Moreover, a negative relation between axial length and the agreement of both methods was detected especially in the 90° meridian (R = −0.38, p = 0.06). PRX measurements tend to underestimate the retinal radius with increasing myopia when compared to OCT measurements. Therefore, future conclusions from PRX on retinal shape should be made cautiously. Rather, faster and more clinically feasible OCT imaging should be performed for this purpose.

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A New Optical Coherence Tomography Method for Subfoveal Choroidal Thickness Measurement: A Single-center Observational Study

10.21203/rs.3.rs-87168/v1 ◽

2020 ◽

Author(s):

Kyung Tae Kang ◽

Ji Hye Jang ◽

Yu Cheol Kim

Keyword(s):

Optical Coherence Tomography ◽

Observational Study ◽

Choroidal Thickness ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

New Method ◽

Optical Coherence ◽

Single Center ◽

Intraclass Correlation Coefficients ◽

Single Center Observational Study

Abstract Background: Several macular pathologies are associated with choroidal vascular supply, and thus require choroidal thickness evaluation. However, there is no standard subfoveal choroidal thickness (SFCT) measuring method. This study investigated a new method to measure the SFCT, using optical coherence tomography.Methods: This is a single-center observational study. Eighty-two senior medical students participated as observers and independently measured the SFCT on five standard optical coherence tomography images of healthy adults in a tertiary care setting. They used three different methods: (1) the observer’s own method, (2) the conventional method, perpendicular to the retinal pigment epithelium, and (3) the new method, along a virtual line connecting the umbo with the most elevated point of the ellipsoid. Additionally, the SFCT angle—the angle between the measurement line and the vertical line of the image—was measured and compared between methods. The intraclass correlation coefficient was used to determine interpersonal variability. Results: The intraclass correlation coefficients for SFCT measured by methods 1, 2, and 3 were 0.853, 0.880, and 0.896, respectively (P < 0.001 for all). It was the highest with method 3; the intraclass correlation coefficients SFCT angles were 0.647, 0.842, and 0.307, respectively (P < 0.001 for all).Conclusions: The new method showed the lowest interpersonal variability, and could therefore be a reliable standard for SFCT measurement, even in foveae with a steep slope on optical coherence tomography.Trial registration: Not applicable

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Reproducibility of Choroidal Thickness Measurements in Hemodialysis Patients. A Spectral Domain Optical Coherence Tomography Study

10.21203/rs.3.rs-522828/v1 ◽

2021 ◽

Author(s):

Özgür Eroğul ◽

Mehmet Murat Uzel ◽

Leyla Eryiğit Eroğul ◽

Ayşe Güzin Taşlıpınar Uzel ◽

Hamidu Hamısı Gobeka ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Choroidal Thickness ◽

Correlation Coefficients ◽

Spectral Domain ◽

Optical Coherence ◽

Single Session ◽

Intra Class Correlation ◽

Coefficients Of Variation ◽

Thickness Measurements ◽

Sd Oct

Abstract PurposeTo investigate the effects of hemodialysis (HD) on the reproducibility of subfoveal choroidal thickness (SFCT) as measured by spectral domain-optical coherence tomography (SD-OCT)MethodsIn this study, 26 HD (26 eyes) patients had their pre- and post-HD SFCT measured, and the results were compared for reproducibility. Following a thorough ophthalmic examination, SD-OCT was performed three times in a row during a single session. The same physician measured SFCT after automatically identifying choroid with a software caliper. The reproducibility parameters, including intra-class correlation coefficients (ICCs), coefficients of variation (COV), and test-retest variability (TRTV) were then calculated.ResultsMales made up 53.85% of the 26 HD patients. There was a significant IOP difference between pre-HD (16.42±3.14 mmHg) and post-HD (14.21±2.78 mmHg) (P<0.001). SFCT decreased significantly from pre-HD 243.50±10.23 μm to post-HD 234.29±9.41 μm (P<0.001). ICC value increased significantly after HD, rising from 0.948 to 0.989 (P<0.001, for all). Pre- and post-HD COV values were 1.6% and 0.65%, respectively. Also, pre- and post-HD TRTV values were 7.864±1.996 μm and 3.074±1.536 μm, respectively.ConclusionThe reproducibility of SFCT as measured by OCT was lower during pre-HD compared to post-HD. Post-HD SD-OCT assessment appears to improve the reliability of clinical outcomes in the diagnosis and monitoring of HD patients.

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Spectral-domain optical coherence tomography for evaluating palisades of Vogt in ocular surface disorders with limbal involvement

Scientific Reports ◽

10.1038/s41598-021-91999-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ying-Yi Chen ◽

Yi-Chen Sun ◽

Chia-Ying Tsai ◽

Hsiao-Sang Chu ◽

Jo-Hsuan Wu ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Ocular Surface ◽

Spectral Domain ◽

Optical Coherence ◽

Slit Lamp ◽

Ocular Rosacea ◽

Unilateral Disease ◽

Healthy Eyes ◽

Slit Lamp Biomicroscopy ◽

Sd Oct

AbstractSpectral-domain optical coherence tomography (SD-OCT) has been used to observe the morphology of the palisades of Vogt (POV) with satisfactory resolutions. In this study, we used SD-OCT to examine the microstructure of the POV in ocular surface disorders with limbal involvement. We detect subclinical limbal pathologies based on five parameters, including (1) decreased epithelial thickness, (2) loss of the sharp stromal tip, (3) loss of the smooth epithelial-stromal interface, (4) dilated stromal vessels, and (5) decreased POV density. Eighteen eyes of 10 patients with advancing wavelike epitheliopathy (AWE) and 15 eyes of 9 patients with phlyctenular keratitis/ocular rosacea were recruited. SD-OCT could detect abnormal changes in the POV in 100% of the lesion sites. In presumed-healthy areas of the diseased eyes diagnosed by slit-lamp biomicroscopy, SD-OCT detected abnormal changes in the POV in 100% of the eyes in both groups. In patients with unilateral disease, abnormal changes in the POV were detected by SD-OCT in 50% and 100% of presumed-healthy eyes diagnosed by slit-lamp biomicroscopy in the AWE group and phlyctenular keratitis/ocular rosacea group, respectively. SD-OCT is powerful in detecting POV changes in ocular surface disorders and can provide useful information that cannot be provided by slit-lamp biomicroscopy.

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Design and Implementation Guidelines for a Modular Spectral-Domain Optical Coherence Tomography Scanner

International Journal of Optics ◽

10.1155/2018/3726207 ◽

2018 ◽

Vol 2018 ◽

pp. 1-22 ◽

Cited By ~ 4

Author(s):

Farid Atry ◽

Israel Jacob De La Rosa ◽

Kevin R. Rarick ◽

Ramin Pashaie

Keyword(s):

Optical Coherence Tomography ◽

Imaging System ◽

Optical Design ◽

Spectral Domain ◽

Design Parameters ◽

Optical Coherence ◽

Custom Made ◽

Essential Knowledge ◽

Sd Oct

In the past decades, spectral-domain optical coherence tomography (SD-OCT) has transformed into a widely popular imaging technology which is used in many research and clinical applications. Despite such fast growth in the field, the technology has not been readily accessible to many research laboratories either due to the cost or inflexibility of the commercially available systems or due to the lack of essential knowledge in the field of optics to develop custom-made scanners that suit specific applications. This paper aims to provide a detailed discussion on the design and development process of a typical SD-OCT scanner. The effects of multiple design parameters, for the main optical and optomechanical components, on the overall performance of the imaging system are analyzed and discussions are provided to serve as a guideline for the development of a custom SD-OCT system. While this article can be generalized for different applications, we will demonstrate the design of a SD-OCT system and representative results for in vivo brain imaging. We explain procedures to measure the axial and transversal resolutions and field of view of the system and to understand the discrepancies between the experimental and theoretical values. The specific aim of this piece is to facilitate the process of constructing custom-made SD-OCT scanners for research groups with minimum understanding of concepts in optical design and medical imaging.

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External limiting membrane: retinal structural barrier in diabetic macular edema

International Journal of Retina and Vitreous ◽

10.1186/s40942-021-00284-x ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Sandeep Saxena ◽

Levent Akduman ◽

Carsten H. Meyer

Keyword(s):

Optical Coherence Tomography ◽

Macular Edema ◽

Diabetic Macular Edema ◽

Spectral Domain ◽

Optical Coherence ◽

Barrier Effect ◽

External Limiting Membrane ◽

Ellipsoid Zone ◽

Structural Barrier ◽

Sd Oct

AbstractAdvances in spectral-domain optical coherence tomography (SD-OCT) technology have enhanced the understanding of external limiting membrane (ELM) and ellipsoid zone (EZ) in diabetic macular edema. An increase in VEGF has been demonstrated to be associated with sequential ELM and EZ disruption on SD-OCT. An intact ELM is a prerequisite for an intact EZ in DME. Anti-VEGF therapy leads to restoration of barrier effect of ELM. The ELM restores first followed by EZ restoration.

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Spectral-Domain Optical Coherence Tomography-Based Morphofunctional Characterization of Dome-Shaped Maculopathy in Indian Population

Journal of Ophthalmology ◽

10.1155/2020/8869455 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Naresh Babu Kannan ◽

Sagnik Sen ◽

Prithviraj Udaya ◽

Obuli Ramachandran ◽

Kim Ramasamy

Keyword(s):

Optical Coherence Tomography ◽

Indian Population ◽

Subretinal Fluid ◽

Cross Sectional Study ◽

Spectral Domain ◽

Dome Height ◽

Optical Coherence ◽

Cross Sectional ◽

Sd Oct

Purpose. To study the clinicodemographic profile of dome-shaped maculopathy (DSM) eyes in the Indian population and characterization using spectral-domain optical coherence tomography (SD-OCT). Methods. This observational cross-sectional study included 25 eyes of 14 patients diagnosed with DSM. All eyes underwent SD-OCT for characterization of the dome profile and also to measure central macular thickness (CMT), subfoveal choroidal thickness (SFCT), and dome height (DH) and to detect the presence of subretinal fluid (SRF). Results. The mean age of patients was 48.36 ± 14.23 years (range, 28–65 years). Eleven patients had bilateral involvement. Mean axial length of all eyes was 24.25 ± 1.95 mm and mean spherical equivalent −4.23 ± 3.79 DS. Overall, 11/25 eyes (44%) had round domes, 9/25 eyes (36%) had horizontal domes, and 5/25 eyes (20%) had vertical domes, with a mean dome height at fovea of 500.54 ± 291.58 µm. Vertical domes had higher DH compared to horizontal or combined domes p = 0.02 . Six eyes (6/25, 24%) showed the presence of SRF; 60% of vertical domes had SRF, and 22.2% of horizontal domes had SRF. The eyes having SRF had significantly higher CMT p = 0.017 and DH p = 0.001 , especially in horizontal domes p = 0.023 . The eyes with thicker SFCT tended to have higher DH and poorer visual acuity. Conclusion. Indian DSM eyes may have relatively lesser amounts of myopia. Choroidal thickening may play a role in development of DSM and may also be related to development of subretinal fluid in such eyes.

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