Automated Measurement of Iris Surface Smoothness Using Anterior Segment Optical Coherence Tomography

Abstract Fuchs uveitis (FU) is a chronic and often unilateral ocular inflammation and characteristic iris atrophic changes, other than heterochromia, are common in FU and are key to the correct diagnosis in many cases. With the advent of anterior segment optical coherence tomography (AS-OCT), some investigators attempted to quantitatively study these atrophic changes; mostly by introducing various methods to measure iris thickness in AS-OCT images. We aimed to present an automated method in a observational case series to measure the smoothness index (SI) of iris surface in AS-OCT images. The ratio of the length of the straight line connecting the most peripheral and central points of the anterior iris border (in nasal and temporal sides) to the actual length of this border on AS-OCT images, was defined as SI. In a uveitis referral center twenty-two eyes of 11 patients with unilateral Fuchs uveitis (FU) (7 female) and 22 eyes of 11 healthy control subjects underwent AS-OCT imaging. Image J and a newly developed MATLAB algorithm were used for manual and automated SI measurements, respectively. Agreement between manual and automated measurements was evaluated with Bland-Altman analysis and interclass correlation coefficient. The inter-eye difference of SI was compared between FU group and control group. Automated mean overall SI was 0.868 ± 0.037 and 0.840 ± 0.039 in FU and healthy fellow eyes, respectively (estimated mean difference = -0.028, 95% CI [-0.038, -0.018], p<0.001). Bland- Altman plots showed good agreement between two methods in both healthy and FU eyes. Interclass correlation coefficient between the manual and automated measurements in the FU and healthy fellow eyes was 0.958 and 0.964, respectively. Inter-eye difference of overall SI was 0.029 ± 0.015 and 0.012 ± 0.008 in FU group and control group, respectively (p=0.01). We concluded that he automated algorithm can rapidly and conveniently measure SI with results comparable to manual method.

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Automated measurement of iris surface smoothness using anterior segment optical coherence tomography

Scientific Reports ◽

10.1038/s41598-021-87954-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mohammad Zarei ◽

Tahereh Mahmoudi ◽

Hamid Riazi-Esfahani ◽

Behnam Mousavi ◽

Nazanin Ebrahimiadib ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Correlation Coefficient ◽

Anterior Segment ◽

Control Group ◽

Optical Coherence ◽

Actual Length ◽

Interclass Correlation Coefficient ◽

Interclass Correlation ◽

Automated Measurements ◽

Fellow Eyes

AbstractFuchs uveitis (FU) is a chronic and often unilateral ocular inflammation and characteristic iris atrophic changes, other than heterochromia, are common in FU and are key to the correct diagnosis in many cases. With the advent of anterior segment optical coherence tomography (AS-OCT), some investigators attempted to quantitatively study these atrophic changes; mostly by introducing various methods to measure iris thickness in AS-OCT images. We aimed to present an automated method in an observational case series to measure the smoothness index (SI) of the iris surface in AS-OCT images. The ratio of the length of the straight line connecting the most peripheral and central points of the anterior iris border (in nasal and temporal sides) to the actual length of this border on AS-OCT images, was defined as SI. In a uveitis referral center, twenty-two eyes of 11 patients with unilateral Fuchs uveitis (FU) (7 female) and 22 eyes of 11 healthy control subjects underwent AS-OCT imaging. Image J and a newly developed MATLAB algorithm were used for manual and automated SI measurements, respectively. Agreement between manual and automated measurements was evaluated with Bland–Altman analysis and interclass correlation coefficient. The inter-eye difference of SI was compared between the FU group and the control group. Automated mean overall SI was 0.868 ± 0.037 and 0.840 ± 0.039 in FU and healthy fellow eyes, respectively (estimated mean difference = − 0.028, 95% CI [− 0.038, − 0.018], p < 0.001). Bland- Altman plots showed good agreement between two methods in both healthy and FU eyes. The interclass correlation coefficient between the manual and automated measurements in the FU and healthy fellow eyes was 0.958 and 0.964, respectively. The inter-eye difference of overall SI was 0.029 ± 0.015 and 0.012 ± 0.008 in FU group and control group, respectively (p = 0.01). We concluded that the automated algorithm can rapidly and conveniently measure SI with results comparable to the manual method.

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99Non-ruptured plaque and platelet-rich thrombi in ST-segment elevation myocardial infarction: new insight into early spontaneous reperfusion

European Heart Journal ◽

10.1093/eurheartj/ehz747.0027 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

J Chen ◽

G Z Wang ◽

Z Liu ◽

Y H Zhang ◽

J C Guo ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Natural Science ◽

Plaque Rupture ◽

Control Group ◽

P Value ◽

Optical Coherence ◽

St Segment Elevation ◽

Plaque Erosion ◽

One Year ◽

And Control

Abstract Objectives To detect the potential mechanism of early spontaneous reperfusion (ESR) in STEMI. Background Early spontaneous reperfusion occurs in around 20% of STEMI and is associated with favorable outcomes. Optical coherence tomography (OCT) is more accurate in detecting subtle morphological details of the culprit lesion. Methods In this prospective study, a total of 107 consecutive patients with STEMI were enrolled from July 2016 to May 2017. Of that total, 21 (19.6%) met the criteria of angiographic ESR (TIMI-3 flow in the initial angiogram). Among those without ESR (TIMI-0 flow in the initial angiogram), 21 patients were assigned into the control group according to propensity score matching with the ESR group. The OCT findings and one-year clinical outcomes were compared between the two groups. Results Although baseline characteristics were comparable, plaque features significantly differed between the ESR and control group (P<0.001), including plaque rupture (23.8% vs. 66.7%), plaque erosion (47.6% vs. 33.3%), calcified nodule (9.5% vs. 0%) and vasospasm (19.1% vs. 0%). Red thrombus (19.1% vs. 85.7%) was far less found whereas white thrombus (61.9% vs. 14.3%) was more common in the ESR group. In addition, despite of less stent placement (0.6±0.5 vs. 1.3±0.9, P<0.001), patients in the ESR group had a non-statistically lower rate of cardiac adverse events (4.8% vs. 14.3%, P=0.269) during one-year follow up. The OCT finding Variables ESR group (n=21) Control group (n=21) P value The OCT imaging <0.001 Plaque erosion 10 (47.6) 7 (33.3) Plaque rupture 5 (23.8) 14 (66.7) Calcified nodule 2 (9.5) 0 (0) Vasospasm 4 (19.1) 0 (0) The Type of Thrombus <0.001 Red thrombus 4 (19.1) 18 (85.7) White thrombus 13 (61.9) 3 (14.3) No thrombus (vasospasm) 4 (19.1) 0 (0) MLA (mm2) 2.7±2.2 2.3±2.4 0.534 Values are n (%), mean ± SD. ESR = early spontaneous reperfusion; MLA = Minimum lumen area; OCT = optical coherence tomography. ESR and control group Conclusions Relief of coronary occlusion induced by non-ruptured plaque and platelet-rich thrombi may be one of the main mechanism underlying early spontaneous reperfusion in STEMI. Acknowledgement/Funding No.81470491 from the National Natural Science Foundation of China and No.7192078 from Beijing Municipal Natural Science Foundation to Dr. Li.

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A pilot study of scleral thickness in central serous chorioretinopathy using anterior segment optical coherence tomography

Scientific Reports ◽

10.1038/s41598-021-85229-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yun Ji Lee ◽

Yeon Jeong Lee ◽

Jae Yeon Lee ◽

Suhwan Lee

Keyword(s):

Optical Coherence Tomography ◽

Central Serous Chorioretinopathy ◽

Anterior Segment ◽

Venous Drainage ◽

Enhanced Depth Imaging ◽

Control Group ◽

Study Group ◽

Optical Coherence ◽

Swept Source ◽

Significant Difference

AbstractThe aim of this study is to compare the scleral thickness of central serous chorioretinopathy (CSC) eyes with controls using anterior segment optical coherence tomography (AS OCT). This prospective case control study included 15 patients (15 eyes) with CSC and 15 age and gender matched healthy subjects. All subjects underwent spectral domain OCT with enhanced depth imaging and swept source AS OCT of temporal sclera. We investigated difference in scleral thickness between the two groups and relationship between choroidal and scleral thickness. Among the 15 eyes in the study group, 1 eye had acute CSC, 4 had recurrent CSC, 7 had inactive CSC, and 3 had chronic CSC. There was no significant difference in terms of age, gender, axial length and spherical equivalent between the two groups. The choroidal and scleral thickness of the study group were significantly greater than those of the control group (P < 0.001, P = 0.034). Choroidal thickness was positively correlated with scleral thickness (P = 0.031). A thick sclera along with a thick choroid were demonstrated in CSC eyes using AS OCT. Scleral characteristics might be involved in the pathogenesis of CSC by affecting outflow resistance of venous drainage in choroidal circulation.

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Corneal optical density in Fuchs endothelial dystrophy determined by anterior segment optical coherence tomography

European Journal of Ophthalmology ◽

10.1177/1120672120944796 ◽

2020 ◽

pp. 112067212094479

Author(s):

Christian M Wertheimer ◽

Carolin Elhardt ◽

Andreas Wartak ◽

Nikolaus Luft ◽

Stefan Kassumeh ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Optical Density ◽

Anterior Segment ◽

Corneal Edema ◽

Diagnostic Tools ◽

Control Group ◽

Distilled Water ◽

Optical Coherence ◽

Corneal Surgery ◽

Disease Characteristics

Purpose: In this study, we propose a method to grade corneal stromal opacity using optical density measurements by anterior segment optical coherence tomography (AS-OCT) and validate the approach in Fuchs endothelial corneal dystrophy (FECD). Methods: A retrospective analysis of human corneal OCT scans was performed on 48 eyes of 32 patients with FECD and 33 control eyes of 21 patients using the Carl Zeiss Cirrus HD-OCT 5000. In addition, corneal edema in fresh rabbit cadaver eyes was artificially induced by distilled water and imaged with the Thorlabs TELESTO-II spectral domain OCT at different time points during saturation. The increase of opacity due to corneal edema was proposed to directly correlate with enhanced reflectivity sites in the OCT images, corresponding to higher optical density. The increase was determined as the image area above a statistically established gray-scale value using ImageJ and correlated with other disease characteristics. Results: Optical densities in human corneas showed significant differences between FECD patients and the control group ( p = 0.002). The increased optical densities determined in FECD corneas correlated well with other disease characteristics such as corneal pachymetry or visual acuity. Likewise, rabbit corneas showed a time dependent increase in thickness and in corneal optical density during soaking in distilled water. Conclusion: This study presents corneal optical density by AS-OCT as an objective value for corneal changes in FECD. Complementing other diagnostic tools in FECD the assessment of corneal optical density may identify progression of FECD, gauge novel therapeutic strategies and support risk and benefit analyses for corneal surgery.

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Role of anterior segment optical coherence tomography angiography in the assessment of acute chemical ocular injury: a pilot animal model study

Scientific Reports ◽

10.1038/s41598-021-96086-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kai Yuan Tey ◽

Jinyuan Gan ◽

Valencia Foo ◽

Bingyao Tan ◽

Meng Yuan Ke ◽

...

Keyword(s):

Animal Model ◽

Optical Coherence Tomography ◽

Optical Coherence Tomography Angiography ◽

Anterior Segment ◽

Ocular Injury ◽

Optical Coherence ◽

Chemical Injury ◽

Highly Correlated ◽

A Prospective Study ◽

And Control

AbstractTo examine the use of anterior segment-optical coherence tomography angiography (AS-OCTA) in the assessment of limbal ischemia in an animal model chemical ocular injury. We conducted a prospective study using an established chemical ocular injury model in 6 rabbits (12 eyes), dividing the cornea limbus into 4 quadrants. Chemical injury grade was induced based on extent of limbal injury (0 to 360 degrees) and all eyes underwent serial slit-lamp with AS-OCTA imaging up to one month. Main outcome measure was changes in AS-OCTA vessel density (VD) comparing injured and control cornea limbal quadrants within 24 h and at one month. AS-OCTA was able to detect differences in limbal VD reduction comparing injured (3.3 ± 2.4%) and control quadrants (7.6 ± 2.3%; p < 0.001) within 24 h of ocular chemical injury. We also observed that AS-OCTA VD reduction was highly correlated with the number of quadrants injured (r = − 0.89; p < 0.001; 95% CI − 5.65 to − 1.87). Corneal vascularization was detected by AS-OCTA in injured compared to control quadrants (10.1 ± 4.3% vs 7.0 ± 1.2%; p = 0.025) at 1 month. Our animal pilot study suggests that AS-OCTA was able to detect limbal vessel disruption from various severities of acute chemical insult, and in the future, could potentially serve as an adjunct in providing objective grading of acute ocular chemical injury once validated in a clinical trial.

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Changes in Langerhans cells and the structure of corneal nerve fibers in patients with glaucoma according in vivo confocal microscopy

POINT OF VIEW EAST – WEST ◽

10.25276/2410-1257-2021-3-30-32 ◽

2021 ◽

pp. 30-32

Author(s):

S.E. Avetisov ◽

◽

V.V. Strahov ◽

Z.V. Surnina ◽

A.A. Popova ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Confocal Microscopy ◽

Langerhans Cells ◽

Structural Changes ◽

Open Angle Glaucoma ◽

Anterior Segment ◽

Nerve Fibers ◽

Control Group ◽

Optical Coherence ◽

Corneal Nerve

The most important tasks of preventing blindness and low vision in primary open-angle glaucoma (POAG) are its early diagnosis and quality monitoring in order to stabilize the glaucoma process. Purpose. To analyze the state of Langerhans inflammatory cells and the structure of corneal nerve fibers in patients with POAG. Material and methods. The study included 46 patients. The main group - 26 patients (52 eyes) aged 39 to 80 years - diagnosed with POAG stages I-IV. Control group - 20 patients (40 eyes) - ophthalmologically healthy volunteers with a normal level of intraocular pressure (IOP) and no signs of POAG at the age from 36 to 72 years. Patients underwent: visometry, biomicroscopy of the anterior segment of the eye, ophthalmoscopy, gonioscopy, contour tonometry using the Pascal method, optical coherence tomography (OCT) of the optic nerve discs (Zeiss Stratus 3000) and confocal microscopy of the cornea (CMR) (HRT III, Rostock Cornea Module). Results. In patients with POAG, according to CMR data, structural changes were revealed in the layer of nerve fibers of the cornea, and abnormalities in the structure and number of inflammatory macrophages (Langerhans cells) were also identified. The interocular asymmetry of CNF was investigated in patients with different stages of glaucoma in paired eyes. Conclusion. Аnalyzing the structure of corneal nerve fibers and Langerhans cells can be used as a diagnostic algorithm in patients with POAG. Key words: glaucoma, confocal microscopy, corneal nerve fibers, Langerhans cells, optical coherence tomography.

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Evaluation of acquired punctal stenosis using anterior segment optical coherence tomography

European Journal of Ophthalmology ◽

10.1177/1120672119871396 ◽

2019 ◽

pp. 112067211987139

Author(s):

Raafat Mohyeldeen Abdelrahman ◽

Heba Radi AttaAllah ◽

Ahmed A Abdelghany ◽

Jorge L Alio

Keyword(s):

Optical Coherence Tomography ◽

Anterior Segment ◽

Normal Subjects ◽

Control Group ◽

Optical Coherence ◽

Diagnostic Modality ◽

Normative Database ◽

Group 2 ◽

Group 1 ◽

Punctal Stenosis

Background/objectives: The aim of this article was to study the lower punctum parameters in patients with acquired punctal stenosis using spectral-domain anterior segment optical coherence tomography. Subjects/methods: This was a prospective nonrandomized study that included two groups. Group 1 was composed of 32 puncta from 32 subjects (11 males and 21 females, aged 40–62 years) with epiphora and clinically diagnosed punctal stenosis. Group 2 (control group) included 30 puncta from 30 normal subjects (10 males and 20 females, aged 43–63 years). Anterior segment optical coherence tomography was employed to evaluate lower punctum parameters in all subjects; the inner and outer punctal diameters as well as punctal depth were measured. Results: External punctal diameter (mean: 466.1 ± 120.3 μm), internal punctal diameter (mean: 173.4 ± 55.6 μm) and punctal depth (mean: 188.4 ± 67 μm) values in Group 1 were statistically significantly lower than those in Group 2 (mean: 745.7 ± 156.9 μm, mean: 384 ± 119.1 μm, and mean: 284.9 ± 57.7 μm, respectively). Conclusion: Anterior segment optical coherence tomography could possibly be used as a noncontact and noninvasive diagnostic modality for evaluating and measuring the lower punctum in patients with punctal stenosis. Further research is required to develop a normative database and grading system for stenosed puncta and to correlate the degree of stenosis with the severity of epiphora.

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Swept Source Optical Coherence Tomography Analysis of a Selected Eye’s Anterior Segment Parameters in Patients with Pseudoexfoliation Syndrome

Journal of Clinical Medicine ◽

10.3390/jcm11010268 ◽

2022 ◽

Vol 11 (1) ◽

pp. 268

Author(s):

Michał Dembski ◽

Anna Nowińska ◽

Klaudia Ulfik-Dembska ◽

Edward Wylęgała

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Pseudoexfoliation Syndrome ◽

Control Group ◽

Optical Coherence ◽

Control Groups ◽

Swept Source ◽

Iridocorneal Angle ◽

Anterior Eye Segment ◽

And Control

Background: Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by the production and accumulation of pseudoexfoliation material. To date, detailed characteristics have not been published regarding the iridocorneal angle and cornea in patients with pseudoexfoliation syndrome determined through swept source optical coherence tomography (SS-OCT). Methods: A total of 150 eyes of patients with pseudoexfoliation syndrome (ages 69–86 years) and 166 eyes in a control group (ages 54–79 years) were analyzed. Results: The central corneal thickness in the PEX group was 549.56 μm and was slightly (insignificantly) higher than that of the control group (540.56 µm). The anterior chamber of the eye was visibly shallower in patients with PEX syndrome than in those of the control group (2.49 mm vs. 3.07 mm; p < 0.001). The Fourier analysis parameters of the cornea showed multiple differences between the PEX and control groups. With respect to iris area, the parameters showed statistically significant differences between the PEX and control groups in all four quadrants of the eye. No statistical significance was found in the PEX group for the iridocorneal angle parameters, or corneal and lens parameters depending on gender and age. Conclusions: PEX syndrome is characterized by a significant impact on the anterior eye segment, including higher anterior and posterior keratometric values, lower anterior chamber depth, higher iris thickness, and narrower angle parameters. The characteristic anterior eye segment features of PEX syndrome can be detected using SS-OCT, which could potentially assist clinicians in properly managing the disease.

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Iris Morphological Features in Patients with 360° Angle-Closure Neovascular Glaucoma: An Anterior Segment Optical Coherence Tomography Study

Case Reports in Ophthalmology ◽

10.1159/000493418 ◽

2018 ◽

Vol 9 (3) ◽

pp. 449-456 ◽

Cited By ~ 1

Author(s):

Yui Kobayashi ◽

Shunsuke Nakakura ◽

Etsuko Terao ◽

Yuki Fujio ◽

Kanae Matsuya ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Trabecular Meshwork ◽

Pupil Diameter ◽

Anterior Segment ◽

Neovascular Glaucoma ◽

Morphological Features ◽

Angle Closure ◽

Control Group ◽

Optical Coherence ◽

Swept Source

Purpose: To investigate iris morphological features in 360° angle-closure neovascular glaucoma (NVG) by swept-source anterior segment optical coherence tomography (ASOCT). Patients and Methods: In this retrospective, clinic-based, comparative study, 14 patients with 360° angle-closure NVG and 14 healthy age-matched control subjects were enrolled. All patients enrolled had no prior glaucoma surgery but underwent cataract surgery with intraocular lens implantation. Horizontal scanning images of swept-source ASOCT were analyzed using software calipers in temporal and nasal angle areas. The iris thickness at 1 and 2 mm from the pupil edge, iris length, trabecular meshwork length, peripheral anterior synechia (PAS) length, PAS height ratio (PAS length/trabecular meshwork length), and pupil diameter were measured. Results: Between the groups, there were no statistically significant differences in iris length, trabecular meshwork length, and pupil diameter (p > 0.05). However, the iris thickness was significantly reduced in the NVG group compared with the control group in the temporal and nasal areas (0.306 vs. 0.563 mm/0.326 vs. 0.645 mm at 1 mm, 0.278 vs. 0.523 mm/0.282 vs. 0.546 mm at 2 mm, respectively) (mean, all p < 0.001). In the NVG group, PAS height ratios were 1.55 ± 0.45 (mean ± standard deviation) (range, 0.58–2.30) and 1.55 ± 0.78 (range, 0.68–3.68) at the temporal and nasal angles, respectively. Conclusions: In patients with 360° angle-closure NVG, the iris thickness decreased to about 50% of that in healthy subjects, and the PAS length exceeded the trabecular meshwork length by about 1.5 times.

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Evaluation of the changes in choroidal thickness in patients with central serous chorioretinopathy as measured by optical coherence tomography

International Eye Research ◽

10.18240/ier.2021.01.06 ◽

2021 ◽

Vol 2 (1) ◽

pp. 31-36

Author(s):

Ragai Magdy Hatata ◽

◽

Sherin Hassan Sadek ◽

Keyword(s):

Optical Coherence Tomography ◽

Central Serous Chorioretinopathy ◽

Choroidal Thickness ◽

Subretinal Fluid ◽

Base Line ◽

Optical Coherence ◽

Significant Difference ◽

And Control ◽

Fellow Eyes

AIM: To study the changes in choroidal thickness in central serous chorioretinopathy (CSCR) over a 3mo follow-up using spectral domain optical coherence tomography (SD-OCT). METHODS: This prospective study included 60 eyes, both eyes of 20 patients (mean age: 33.65±5.24y) with classic acute unilateral central serous chorioretinopathy and normal fellow eye and 20 eyes as healthy controls. Fluorescein angiography and OCT were done. The subfoveal choroidal thickness (SFCT), central macular thickness (CMT), 1000 μm temporal and nasal to the centre of the fovea and the subretinal fluid were measured. RESULTS: There was a statistically significant difference in SFCT among the three groups at the three different locations. SFCT in eyes with CSCR (372.40±34.39 μm) was significantly greater than that in each of the unaffected fellow eyes (302.10±8.9 μm) and control eyes (279.80±14.49 μm) at the base line and after 3mo follow-up. The mean CMT in CSCR was 317±141.86 μm, with a statistically significant positive correlation between SFCT and CMT. CONCLUSION: The increase in the choroidal thickness at different locations as well as hyper-dilated and hyper-permeable vessels known as “pachychoroid” seems to play an important role in a broad spectrum of diseases that includes central serous chorioretinopathy.

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