Feature Based Differentiator for Fluid Filled Retinal Abnormalities in Retina Using Optical Coherence Tomography Images

2020 ◽  
Vol 10 (3) ◽  
pp. 566-571
Author(s):  
K. Venkatraman ◽  
M. Sumathi
Keyword(s):  
Optical Coherence Tomography ◽  
Vision Loss ◽  
Fluid Collection ◽  
Wiener Filter ◽  
Detection Algorithm ◽  
Processing Technique ◽  
Input Image ◽  
Optical Coherence ◽  
Significant Difference ◽  
Overall Performance

Introduction: The Optical Coherence Tomography is widely used in ophthalmic imaging to assess the condition of retina. It serves as an effective tool in diagnosing various fluid related abnormalities in retina, which are prior stages to vision loss. The overall pattern of fluid collection is a vital tool in disease identification. Aim: To classify various fluid filled retinal abnormalities, like, Cystoid Macular Edema (CME), Choroidal Neo Vascular Membrane (CNVM), and Macular Hole (MH) based on various features. Materials and Methods: A total of 114 images were acquired using TOPCONN and ZEISS OCT devices. The obtained images were converted to grayscale and subjected to pre-processing technique. Homomorphic Wiener filter was used to remove the speckle noises. The Region of Interest was then identified by basic edge detection algorithm, for which, various features were extracted and utilised for classification. Outputs were cross verified with a medical expert and the performance of the proposed system was evaluated. Results: Based on the proposed system of classification of various fluid filled retinal disorders, the input image was classified as Class 0—Normal, Class 1—CME, Class 2—CNVM, and Class 3—MH based on the pattern of fluid accumulation. The overall performance was compared and evaluated and it was identified that the system exhibited 91.65% accuracy, 90.36% Sensitivity, 92.95% Specificity and Youden's Index value of 0.83. Conclusion: As OCT serves an important tool for pre-screening of blindness, automations in these areas remains of higher potential. The classification is based on the features used, which showed a significant difference between the various classes as classified. The overall performance seems to be satisfactory and would thus help in early detection of fluid related abnormalities and also can be used as an expert tool to analyse the efficiency of the therapies.

Enhanced-Resolution Optical Coherence Tomography Imaging

2016 ◽  
Vol 235 (3) ◽  
pp. 163-172 ◽  
Author(s):  
Akihito Uji ◽  
Tomoaki Murakami ◽  
Shigeta Arichika ◽  
Yuki Muraoka ◽  
Shin Yoshitake ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Image Quality ◽  
Super Resolution ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Optical Coherence ◽  
Enhanced Resolution ◽  
Opinion Score ◽  
Significant Difference ◽  
Bicubic Interpolation

Purpose: The effect of the enhanced-resolution imaging (ERI) technique on optical coherence tomography (OCT) images was evaluated. Methods: A total of 5 healthy subjects and 20 patients diagnosed with various eye diseases were recruited into the study. ERI, a novel image processing technique, was accomplished by using super-resolution technology, and was assessed by objectively and subjectively comparing the image quality among three different image groups: images enlarged without bicubic interpolation (NONE), with bicubic interpolation (IP), and with ERI. Results: ERI showed a higher ratio of the detailed variance to the background variance than NONE, whereas no significant difference was detected between NONE and IP. The mean opinion score of 5 experienced retinal specialists for ERI was significantly higher than that for IP. Conclusions: ERI generated a sharper image and clearly visualized small objects. Additionally, it is effective in enhancing OCT image quality.

scholarly journals Swept Source Optical Coherence Tomography Angiography for Contact Lens-Related Corneal Vascularization

2016 ◽  
Vol 2016 ◽  
pp. 1-3 ◽  
Author(s):  
Marcus Ang ◽  
Yijun Cai ◽  
Anna C. S. Tan
Keyword(s):  
Optical Coherence Tomography ◽  
Image Quality ◽  
Contact Lens ◽  
Optical Coherence Tomography Angiography ◽  
Quality Score ◽  
Image Quality Score ◽  
Optical Coherence ◽  
Swept Source ◽  
Corneal Vascularization ◽  
Significant Difference

Purpose. To describe a novel technique of adapting a swept-source optical coherence tomography angiography (OCTA) to image corneal vascularization.Methods. In this pilot cross-sectional study, we obtained 3 × 3 mm scans, where 100,000 A-scans are acquired per second with optical axial resolution of 8 μm and lateral resolution of 20 μm. This was performed with manual “XYZ” focus without the anterior segment lens, until the focus of the corneoscleral surface was clearly seen and the vessels of interest were in focus on the corresponding red-free image. En face scans were evaluated based on image quality score and repeatability.Results. We analyzed scans from 10 eyes (10 patients) with corneal vascularization secondary to contact lens use in 4 quadrants, with substantial repeatability of scans in all quadrants (mean image quality score 2.7 ± 0.7;κ=0.75). There was no significant difference in image quality scores comparing quadrants (superior temporal: 2.9 ± 0.6, superior nasal: 2.8 ± 0.4, inferior temporal: 2.5 ± 0.9, and inferior nasal: 2.4 ± 1.0;P=0.276) and able to differentiate deep and superficial corneal vascularization.Conclusion. This early clinical study suggests that the swept-source OCTA used may be useful for examining corneal vascularization, which may have potential for clinical applications such as detecting early limbal stem cell damage.

Progressive, Symmetrical, Painless Visual Loss

2021 ◽  
pp. 77-79
Author(s):  
Eric R. Eggenberger ◽  
Marie D. Acierno ◽  
M. Tariq Bhatti ◽  
John J. Chen
Keyword(s):  
Optical Coherence Tomography ◽  
Vision Loss ◽  
Fundus Autofluorescence ◽  
Retinal Pigment ◽  
Light Sensitivity ◽  
Normal Serum ◽  
Breast Adenocarcinoma ◽  
Optical Coherence ◽  
Autoimmune Retinopathy ◽  
Cancer Associated Retinopathy

A 75-year-old woman with a medical history of mixed connective tissue disease and breast adenocarcinoma sought care for subacute visual “haze” in both eyes characterized by light sensitivity, particularly with commercial fluorescent lighting, progressing over weeks. Visual acuity was 20/40 in each eye. The pupils were equal in size with no relative afferent pupillary defect but were sluggishly reactive to light. Automated perimetry documented peripheral constriction in both eyes. Ocular motility was normal. Ophthalmoscopy showed mild retinal pigment epithelial changes in both maculae with normal optic nerves. Optical coherence tomography showed macular thinning in both eyes. Findings of fundus autofluorescence were normal. Serum testing documented the presence of 3 retinal antibodies, against 30-, 36-, and 46-kDa proteins. A paraneoplastic panel was negative except for low-level ganglionic (alpha 3) acetylcholine receptor autoantibody positivity, which was interpreted as nonspecific autoimmunity. Electroretinography indicated severely decreased scotopic and photopic a and b waves. A diagnosis of paraneoplastic or nonparaneoplastic autoimmune retinopathy was made, consistent with the clinical presentation, optical coherence tomography and electroretinography findings, and the presence of retinal antibodies. There are no established evidence-based guidelines to assist treatment decisions in autoimmune retinopathy, although several lines of therapy have been advocated. No specific immunosuppressive therapy was undertaken in this case. However, if her vision had continued to rapidly worsen over time, empiric immunotherapy would have been instituted. Autoimmune retinopathy includes paraneoplastic and nonparaneoplastic forms. The best-characterized autoimmune retinopathy phenotype is cancer-associated retinopathy. Cancer-associated retinopathy typically presents with subacute, painless, bilateral (although asymmetry has been described) vision loss that is progressive over weeks to months, reflecting both rod and cone dysfunction in most patients. Visual symptoms precede recognition of an underlying cancer in approximately 50% of cases.

scholarly journals Evaluation of Crack Formation and Propagation with Ultrasonic Root-End Preparation and Obturation Using a Digital Microscope and Optical Coherence Tomography

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Bayan Rashed ◽  
Yoshiko Iino ◽  
Arata Ebihara ◽  
Takashi Okiji
Keyword(s):  
Optical Coherence Tomography ◽  
Crack Formation ◽  
Mineral Trioxide Aggregate ◽  
Optical Coherence ◽  
Micro Ct ◽  
Weak Correlation ◽  
Significant Difference ◽  
Digital Microscope ◽  
Ultrasonic Preparation ◽  
End Resection

Objective. This study is aimed at determining (1) the effect of root-end resection, ultrasonic root-end preparation, and root-end filling on the incidence of crack formation and propagation by using a digital microscope (DM) and optical coherence tomography (OCT) and (2) the performance of OCT on the detection of cracks by comparing with microcomputed tomography (micro-CT) as a reference standard. Methodology. Thirty extracted lower incisors were endodontically treated and subjected to root-end resection and ultrasonic root-end cavity preparation. Then, the teeth were divided into three groups (n=10, each), and the root-end cavity was either left unfilled or filled with mineral trioxide aggregate (MTA) or super-EBA. The resected surface was observed with OCT and DM after the root-end resection, ultrasonic root-end preparation, and root-end filling, and the frequency of incomplete and complete cracks were recorded. The observation was repeated after two weeks, one month, and two months, and micro-CT scans after two months were taken as the gold standard. Results. The DM results show dentinal crack formation in 47% of the samples following root-end resection and in 87% following ultrasonic preparation. After the ultrasonic preparation, no existing crack propagated to a complete crack, but new cracks were formed. MTA and super-EBA had no effect on crack formation. The Spearman correlation coefficient between OCT and DM was 0.186 (very weak correlation; p=0.015). Sensitivity and specificity in comparison to micro-CT were 0.50 and 0.55 in OCT and 1.00 and 0.35 in DM, respectively. McNemar’s test showed a significant difference between OCT and DM (p<0.05). Conclusion. Apical resection and ultrasonic preparation could form dentinal cracks. OCT and DM showed different detection frequencies of cracks with very weak correlation. DM showed superior sensitivity compared with OCT.

scholarly journals Repeatability of ocular surface vessel density measurements with optical coherence tomography angiography

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Sijie Cai ◽  
Fengping Zhao ◽  
Chixin Du
Keyword(s):  
Optical Coherence Tomography ◽  
Ocular Surface ◽  
Optical Coherence Tomography Angiography ◽  
Imaging System ◽  
Intraclass Correlation ◽  
Vessel Density ◽  
Optical Coherence ◽  
Significant Difference ◽  
Surface Vessel ◽  
Healthy Eyes

Abstract Background To determine the repeatability of measurements of ocular surface vessel density in normal and diseased eyes using optical coherence tomography angiography (OCTA). Methods Ten normal eyes, 10 pinguecula eyes, and 10 pterygium eyes of 30 volunteers were subjected to OCTA (AngioVue Imaging System, Optovue, Inc.). For scanning, we used the corneal adapter module. Each eye was scanned three times in the nasal and temporal directions, separately. AngioVue software was used to generate the ocular surface vessel density. Ocular surface vessel density was defined as the proportion of vessel area with blood flow to the total measurement area (3 × 3 mm2). Intersession repeatability of the measurement was summarized as the coefficient of variation (CV), and intraclass correlation coefficients (ICC) were calculated by variance component models. Results The CVs were less than 5% in all subjects, and the ICCs exceeded 0.9; thus, all measurements showed good repeatability. The nasal vessels densities differed significantly between healthy eyes and eyes with pterygium (P < 0.05); however, there was no significant difference between healthy eyes and eyes with pinguecula (P = 0.466). Conclusions These results suggest that measurement of ocular surface vessel density by OCTA in normal eyes and eyes with pterygium and pinguecula is repeatable. This preliminary research describes a quantitative and visual method for assessing vessel density of the ocular surface with a high level of consistency.

scholarly journals Comparison of two different optical coherence tomography angiography devices in detecting healthy versus glaucomatous eyes – an observational cross-sectional study

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
A. R. Kee ◽  
V. C. H. Yip ◽  
E. L. T. Tay ◽  
C. W. Lim ◽  
J. Cheng ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diagnostic Accuracy ◽  
Optic Disc ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Swept Source ◽  
Retest Reliability ◽  
Significant Difference ◽  
Test Retest Reliability

Abstract Background To understand the differences between two different optical coherence tomography angiography (OCTA) devices in detecting glaucomatous from healthy eyes by comparing their vascular parameters, diagnostic accuracy and test-retest reliability. Methods A cross-sectional observational study was performed on healthy and glaucoma subjects, on whom two sets of OCTA images of optic disc and macula were acquired using both AngioVue (Optovue, USA) and Swept Source (Topcon, Japan) OCTA devices during one visit. A novel in-house software was used to calculate the vessel densities. Diagnostic accuracy of the machines in differentiating healthy versus glaucomatous eyes was determined using area under the receiver operating characteristic curve (AUROC) and test-retest repeatability of the machines was also evaluated. Results A total of 80 healthy and 38 glaucomatous eyes were evaluated. Glaucomatous eyes had reduced mean vessel density compared to healthy controls in all segmented layers of the optic disc and macula using AngioVue (p ≤ 0.001). However, glaucomatous eyes had higher mean vessel density on optic disc scans using Swept Source, with lack of statistically significant difference between healthy and glaucomatous eyes. The AUROC showed better diagnostic accuracy of AngioVue (0.761–1.000) compared to Swept Source (0.113–0.644). The test-retest reliability indices were generally better using AngioVue than Swept Source. Conclusions AngioVue showed better diagnostic capability and test-retest reliability compared to Swept Source. Further studies need to be undertaken to evaluate if there is any significant difference between the various machines in diagnosing and monitoring glaucoma.

Effects of Retinal Angiography on Optical Coherence Tomography Measurements

2015 ◽  
Vol 234 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Young-Joon Jo ◽  
Hyung-Bin Lim ◽  
Soo-Hyun Lee ◽  
Jung-Yeul Kim
Keyword(s):  
Optical Coherence Tomography ◽  
Indocyanine Green ◽  
Retinal Thickness ◽  
Optical Coherence ◽  
Fiber Layer ◽  
Nerve Fiber Layer Thickness ◽  
Interclass Correlation ◽  
Significant Difference ◽  
Before And After ◽  
Sd Oct

Purpose: To evaluate the effects of retinal angiography, using fluorescein and indocyanine green dyes, on optical coherence tomography (OCT) measurements. Methods: In total, 76 eyes from 76 consecutive patients were included. Macular cube 512 × 128 combination scanning and optic disc 200 × 200 scanning using spectral-domain (SD)-OCT were performed twice, before and after retinal angiography, with fluorescein or indocyanine green. Signal strength, regional retinal thickness of the 9 Early Treatment Diabetic Retinopathy Study subfields, total macular volume, and retinal nerve fiber layer thickness obtained before and after angiography were compared. Repeatability was also investigated. Results: Comparing the results of OCT measured before and after retinal angiography, there was no statistically significant difference in any parameter assessed. The interclass correlation values for each measurement were all >0.808 (range 0.808-0.999). Conclusion: Retinal angiography using fluorescein and indocyanine green dyes has no significant effect on OCT measurements.

scholarly journals Optical Coherence Tomography Reveals New Insights into the Accommodation Mechanism

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Mahmoud Mohamed Farouk ◽  
Takeshi Naito ◽  
Kayo Shinomiya ◽  
Hiroshi Eguchi ◽  
Khulood Mohammed Sayed ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Outcome Measures ◽  
Anterior Segment ◽  
Case Series ◽  
Optical Coherence ◽  
Anterior Pole ◽  
Forward Movement ◽  
Anterior Segment Oct ◽  
Lens Thickness ◽  
Significant Difference

Purpose. To evaluate the movement of the anterior and posterior lens poles during naturally stimulated accommodation in children using anterior segment optical coherence tomography (OCT).Methods. This is a prospective, observational, noncomparative case series including 18 eyes of nine children. Analysis of the anterior segment in the accommodated and unaccommodated state (with cycloplegia) was done using anterior segment OCT. The main outcome measures were the position of the anterior and posterior lens poles (in relation to the cornea) and lens thickness (LT).Results. A Statistically significant forward movement of the anterior lens pole and backward movement of the posterior lens pole with an increase in LT were found during accommodation (P<0.001). There was no significant difference between the degree of movement of the anterior lens pole and the posterior lens pole during accommodation (P=0.944).Conclusions. Anterior segment OCT provides a rapid noncontact method for studying accommodation in children. The backward movement of the posterior lens pole during accommodation nearly equals the forward movement of its anterior pole. These data minimize the theoretical hydraulic effect of the vitreous during accommodation, adding more support to the capsular theory of Helmholtz.

OCT Angiography of the Central Macular Capillary Network in Glaucoma Patients and Healthy Controls

2018 ◽  
Vol 235 (04) ◽  
pp. 436-444
Author(s):  
Olena Müller ◽  
Margarita G. Todorova ◽  
Torsten Schlote
Keyword(s):  
Optical Coherence Tomography ◽  
Structural Changes ◽  
Ganglion Cells ◽  
Retinal Nerve Fibre Layer ◽  
Vessel Density ◽  
Healthy Controls ◽  
Optical Coherence ◽  
Significant Difference ◽  
Nerve Fibre Layer ◽  
And Control

Abstract Purpose We aimed to investigate central macular microvasculature by optical coherence tomography angiography (OCTA) and to analyse its relation to alterations in classical parameters of optical coherence tomography (OCT) in glaucoma patients. Methods Using OCTA (Avanti incl. AngioVue; Optovue, Inc., Fremont, CA), the superficial flow (SF) and the superficial non-flow (SNF) area of the macula, as well as the S-ETDRS (based on Early Treatment Diabetic Retinopathy charts). and S-grid vessel density (zones 1 – 9) of the macula, were evaluated in 27 glaucoma patients (49 eyes) and compared to those of 27 age-matched healthy controls (50 eyes; p = 0.253). The interactions between OCTA parameters representing macular microvasculature and classical OCT measurements of the circumpapillary retinal nerve fibre layer (RNFL) and macular ganglion cells (mGCC) were analysed within groups (linear mixed-effects model). Results SF, SNF, and S-ETDRS vessel density exhibited no significant difference between the glaucoma and control groups (all p ≥ 0.158). However, within the glaucoma group, decreased RNFL and mGCC thickness correlated significantly with decreased S-ETDRS density (zones 1; 2 – 9, p ≤ 0.033). The same held true for the interactions between the RNFL and mGCC thickness with S-grid density (zones 1 – 3; 6 – 9; p ≤ 0.033). For perimetric glaucoma patients, subgroup analyses demonstrated significantly reduced density maps of superficial foveal flow as well as significant interactions between OCT and OCTA parameters; this was not the case within the preperimetric group. Conclusions Even if the central macular microvasculature, as measured by SF and SNF, is found preserved in glaucoma, the strong positive relation between the central microvascular and structural changes in OCTA and OCT indicates that there are alterations in central macular microvasculature in subclinical glaucoma.

scholarly journals Optical Coherence Tomography Angiography Imaging to monitor Anti-VEGF treatment of Corneal Vascularization in a Rabbit Model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kavya Devarajan ◽  
Hon Shing Ong ◽  
Nyein C. Lwin ◽  
Jacqueline Chua ◽  
Leopold Schmetterer ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Imaging Technique ◽  
Anterior Segment ◽  
Rabbit Model ◽  
Saline Group ◽  
Optical Coherence ◽  
Conjunctival Injection ◽  
Anti Vegf ◽  
Significant Difference

AbstractOptical coherence tomography angiography (OCTA) is a well-established non-invasive retinal vascular imaging technique. It has been recently adapted to image the anterior segment and has shown good potential to image corneal vascularisation. The purpose of the study is to evaluate the usefulness of OCTA to monitor regression of corneal vessels following anti-VEGF (vascular endothelial growth factor) treatment using a previously established corneal vascularisation rabbit model. The regression of vessels following the treatment with aflibercept and ranibizumab anti-VEGFs using both topical instillation and sub-conjunctival injection was quantified using OCTA and compared with ICGA (indocyanine green angiography). Overall vessel density measurements using OCTA showed good correlation (r = 0.988, p < 0.001) with ICGA, with no significant difference between the two treatment groups (p = 0.795). It was also shown that OCTA provided good repeatability outcomes of the quantitative measurements. Using Bland-Altman plots, vessel growth density values between anti-VEGF treatments were compared to control saline group. It was observed that aflibercept provided longer lasting effect than ranibizumab. We also observed that in both drugs, the topical route of administration topical provided longer regression outcomes compared to one-time sub-conjunctival injection. Thereby, with this pilot study, it was demonstrated that OCTA is a reliable imaging technique to follow-up and monitor corneal vascularisation and its treatment quantitatively.

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