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Anatomical Characterization of an Optic Disc Notch Using SD-OCT in Glaucoma
摘要： Purpose: To characterize anatomical dimensions of a disc notch using novel methods using spectral domain optical coherence tomography (SD-OCT). Participants: All age- and severity-matched glaucoma patients with disc notch (defined as complete loss of neural rim with no residual rim between disc and cup) seen from 2014 to 2015 who underwent enhanced depth imaging with SD-OCT (Cirrus HD-OCT version 6.5, Carl Zeiss, USA) were included for this retrospective observational study. Methods: Using known dimensions of the 200 * 200 optic disc cube (6 * 6 mm), the notch width was calculated from the margins of the notch on either side using ImageJ software. The height was calculated from the lowest margin of the cup to the lowest point of the defect on the optic disc. These were compared with the quadrant retinal nerve fiber layer (qRNFT) and sectoral retinal nerve fiber layer (sRNFLT) thickness in notch and the sector 2 clock hours adjacent to the notch region (SaRNFLT). Results: The height and width of the notch in 31 eyes of 27 patients were 2.6 ± 0.48 mm and 2.23 ± 0.31 mm. The RNFL thickness in the same sector as that of the notch was 41 ± 21.06 μm while the adjacent two sectors measured 62 ± 26.5 and 64 ± 26.5 μm on either sides of the sector of the notch. The difference between the sRNFLT and saRNFLT ranged from ?9 to 67 and ?13 to 50 μm, respectively. This difference was significantly associated with height of the notch (R2 = 20.8, p = 0.01). Conclusion: Automated analysis of a notch and RNFL thickness in that sector can help in precise glaucoma monitoring in the region of interest.
关键词： glaucoma,optic disc pit,Optical coherence tomography,lamina cribrosa,optic disc notch
更新于2025-09-23 15:21:01
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Asymmetry of Retinopathy of Prematurity Border in the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity Study
摘要： Purpose: To measure the location of the retinopathy of prematurity (ROP) border in a sample of premature infants who developed ROP and determine location for predicting subsequent development of referral-warranted ROP (RW-ROP, defined as Stage 3 ROP, zone I ROP, or plus disease) or treated ROP. Design: Secondary analysis of data from an observational cohort study, The Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity (e-ROP) study. Subjects: Infants with birth weight (BW) less than 1251g with at least one exam and image session at ≤34 weeks postmenstrual age (PMA) with ROP not meeting RW-ROP, and at least one subsequent exam at ≥36 weeks PMA. Methods: The 5-image set from the first imaging session for each eligible eye was mosaicked, and measurements of the ROP border in each mosaicked image were made using Image J. Measurements were compared among 3 groups of eyes with ROP: (1) never developed RW-ROP or received treatment, (2) developed RW-ROP but did not receive treatment, and (3) received treatment; using analysis of variance and linear trend tests that accounted for the inter-eye correlation. Main outcome measures: RW-ROP, treated ROP Results: 317 eyes from 217 infants with mean BW 755g, mean GA 25 weeks, and mean PMA 33 weeks at first exam met study criteria. Of 211 (66.6%) eyes with sufficient quality images for grading, 147 (69.7%) did not develop RW-ROP or receive treatment, 36 (17.1%) developed RW-ROP not requiring treatment, and 28 (13.3%) received treatment for ROP. Among all eyes, the disc-to-ROP border distance followed a consistent pattern, with nasal < inferior < superior < temporal. Eyes that developed RW-ROP or underwent treatment had significantly shorter nasal and temporal disc-to-ROP border distances and smaller areas of retina within the ROP border. In multivariate analysis adjusted by BW and GA, nasal ROP border distance was a significant predictor of developing treated ROP (OR=0.86 for every 10 pixel increase in distance, p=0.002). Conclusions: ROP is located asymmetrically around the optic disc and is closest to the optic disc nasally. Location of ROP nasally at first imaging is a significant predictor of developing treated ROP.
关键词： retinopathy of prematurity,ROP,asymmetry,telemedicine,optic disc
更新于2025-09-23 15:21:01
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Automatic computer-aided analysis of optic disc pallor in fundus photographs
摘要： Purpose: Assessment of optic disc pallor in fundus photographs may be frequently misinterpreted due to the subjective nature of interpretation. We developed a fully automatic computer-aided detection (CAD) system for optic disc pallor using colour fundus photographs and evaluated the accuracy of the system. Methods: A newly proposed CAD system was developed for automated segmentation and image analysis of optic disc pallor, and a logistic regression model was developed for risk analysis. A total of 230 photographs with variable degree of optic disc pallor, and 123 normal optic discs confirmed by optical coherence tomography were tested for validation of the software. Sensitivity and specificity of the CAD system in automatic detection of optic disc pallor using colour fundus photographs were evaluated. The results of manual detection of optic disc pallor on fundus photographs by two independent ophthalmologists were compared with the efficacy of the CAD system. Results: The fully automated CAD system achieved a sensitivity of 95.3% and a specificity of 96.7% for detecting optic disc pallor in colour fundus images. The overall accuracy of the CAD system was 96.1%, which was superior to the results of manual detection by individual examiners. Conclusions: We developed an automated CAD system that successfully detected optic disc pallor in fundus photographs. The proposed algorithm can assist the clinical judgement of ophthalmologists for detecting optic disc pallor in fundus photographs.
关键词： automatic,computer-aided detection,optic disc,pallor
更新于2025-09-11 14:15:04
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A practical approach to estimating optic disc dose and macula dose without treatment planning in ocular brachytherapy using 125I COMS plaques
摘要： Background: It has been reported that proximity of the tumor to the optic disc and macula, and radiation dose to the critical structures are substantial risk factors for vision loss following plaque brachytherapy. However, there is little dosimetry data published on this. In this study, therefore, the relationship between distance from tumor margin and radiation dose to the optic disc and macula in ocular brachytherapy using 125I Collaborative Ocular Melanoma Study (COMS) plaques was comprehensively investigated. From the information, this study aimed to allow for estimation of optic disc dose and macula dose without treatment planning. Methods: An in-house brachytherapy dose calculation program utilizing the American Association of Physicists in Medicine Task Group-43 U1 formalism with a line source approximation in a homogenous water phantom was developed and validated against three commercial treatment planning systems (TPS). Then optic disc dose and macula dose were calculated as a function of distance from tumor margin for various tumor basal dimensions for seven COMS plaques (from 10 mm to 22 mm in 2 mm increments) loaded with commercially available 125I seeds models (IAI-125A, 2301 and I25.S16). A prescribed dose of 85 Gy for an irradiation time of 168 h was normalized to a central-axis depth of 5 mm. Dose conversion factors for each seed model were obtained by taking ratios of total reference air kerma per seed at various prescription depths (from 1 mm to 10 mm in 1 mm intervals) to that at 5 mm. Results: The in-house program demonstrated relatively similar accuracy to commercial TPS. Optic disc dose and macula dose decreased as distance from tumor margin and tumor basal dimension increased. Dose conversion factors increased with increasing prescription depth. There existed dose variations (<8%) among three 125I seed models. Optic disc dose and macula dose for each COMS plaque and for each seed model are presented in a figure format. Dose conversion factors for each seed model are presented in a tabular format. Conclusions: The data provided in this study would enable clinicians in any clinic using 125I COMS plaques to estimate optic disc dose and macula dose without dose calculations.
关键词： Ocular brachytherapy,Optic disc dose,COMS plaques,125I,Macula dose
更新于2025-09-11 14:15:04
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[IEEE 2018 37th Chinese Control Conference (CCC) - Wuhan (2018.7.25-2018.7.27)] 2018 37th Chinese Control Conference (CCC) - Computer Aided Diagnosis for Diabetic Retinopathy based on Fundus Image
摘要： Diabetic Retinopathy (DR) is an eye abnormality caused by long term diabetes, which can lead to vision defects or even blindness. Performing retinal screening examinations on all diabetic patients is a hard work due to the limited number of specialists cannot keep up with the increasing prevalence of diabetes, and hence there are many undiagnosed and untreated cases of DR. Computer aided diagnosis (CAD) is a good way to save the patient’s vision and to help the ophthalmologists in mass screening of diabetes sufferers. The main purpose of the proposed study is to design an automated grading approach for DR screening, using a publicly available database of retinal images, which can evaluate the fundus images like human experts while achieving a high sensitivity for the detection of DR. This paper gives a summary of the results obtained by our previous studies. Together with these results and the DR grading schemes, we provide an automatic analysis approach for the risk of macular edema and the retinopathy grade. Experimental results indicate that the performance of our approach on this database is comparable to that of human experts.
关键词： Optic disc,Macula,Diabetic Retinopathy,Pattern Recognition,Exudates
更新于2025-09-10 09:29:36
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A Novel Approach for Diagnosing Diabetic Retinopathy in Fundus Images
摘要： In recent years the medical profession has seen an ever increasing demand for diagnosis and a permanent cure for illnesses caused by climatic-changes, unwholesome food and environmental pollution. Also the appearances of hitherto unknown viral diseases have caused eye diseases, which have prompted surgeons to monitor the health of the eyes. Potential new therapies that may help in preserving sight in the growing population of diabetic patients into the 21st Century. Early detection of diseases affecting the eyes reduces the risk of permanent damage. Some of the serious conditions which warrant early diagnosis are: Glaucoma, floaters, macula degradation and diabetic retinopathy. In the early stages, a choice of treatment options exist, which dwindles as the disease spreads. A visual inspection of the optic disc, macula and the blood vessels of the eye requires to be done routinely. Diabetic patients run the risk of damage to retinal vessels, which are referred to as diabetic retinopathy. This may further be classified as: Non-proliferative diabetic retinopathy and proliferative diabetic retinopathy. In scientific literatures, feature extraction method has been reported for diagnosis and classification. In this study a systematic Decide, Detect, Determine and Do approach for analyzing diabetic retinopathy images has been taken up. The proposed approach gives a clearer picture of the abnormality, its type (NPDR or PDR), its status (viz., mild, moderate or severe) and finally the appropriate treatment.
关键词： Macula,Diabetic Retinopathy,PDR,Blood Vessels,NPDR,Optic Disc
更新于2025-09-10 09:29:36
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Localization and segmentation of optic disc in retinal images using Circular Hough transform and Grow Cut algorithm
摘要： Automated retinal image analysis has been emerging as an important diagnostic tool for early detection of eye-related diseases such as glaucoma and diabetic retinopathy. In this paper, we have presented a robust methodology for optic disc detection and boundary segmentation, which can be seen as the preliminary step in the development of a computer-assisted diagnostic system for glaucoma in retinal images. The proposed method is based on morphological operations, the circular Hough transform and the grow-cut algorithm. The morphological operators are used to enhance the optic disc and remove the retinal vasculature and other pathologies. The optic disc center is approximated using the circular Hough transform, and the grow-cut algorithm is employed to precisely segment the optic disc boundary. The method is quantitatively evaluated on five publicly available retinal image databases DRIVE, DIARETDB1, CHASE_DB1, DRIONS-DB, Messidor and one local Shifa Hospital Database. The method achieves an optic disc detection success rate of 100% for these databases with the exception of 99.09% and 99.25% for the DRIONS-DB, Messidor, and ONHSD databases, respectively. The optic disc boundary detection achieved an average spatial overlap of 78.6%, 85.12%, 83.23%, 85.1%, 87.93%, 80.1%, and 86.1%, respectively, for these databases. This unique method has shown significant improvement over existing methods in terms of detection and boundary extraction of the optic disc.
关键词： Optic disc,Image analysis,Glaucoma detection,Retinal image analysis,Growcut algorithm
更新于2025-09-10 09:29:36
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[IEEE 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Tirunelveli, India (2018.5.11-2018.5.12)] 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Analysis of CDR of Fundus Images for Glaucoma Detection
摘要： Glaucoma is the second leading cause of blindness in the world. It is estimated that 66.8 million people in the world have glaucoma, with 6.7 million bilaterally blind from this disease. There are no early symptoms of glaucoma and the only source to detect glaucoma at early stage is the structural change that arises in the internal eye. Many autonomous glaucoma detection systems analyze fundus image by calculating its Cup to Disc Ratio (CDR) and categorize the image as glaucoma or healthy. This paper is on image processing technique for the early detection of glaucoma. In this paper glaucoma is detected using retinal fundus image. CDR technique is used on different retinal image for glaucoma detection. Further, analysis of CDR is carried out using different color channel combinations of the fundus images.
关键词： Optic Cup,Glaucoma,CDR,Fundus Image,Optic Disc
更新于2025-09-09 09:28:46
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Segmentation and Classification of Optic Disc in Retinal Images
摘要： Image segmentation plays a vital role in image analysis for diagnosis of various retinopathy diseases. For the detection of glaucoma and diabetic retinopathy, manual examination of the optic disc is the standard clinical procedure. The proposed method makes use of the circular transform to automatically locate and extract the Optic Disc (OD) from the retinal fundus images. The circular transform operates with radial line operator which uses the multiple radial line segments on every pixel of the image. The maximum variation pixels along each radial line segments are taken to detect and segment OD. The input retinal images are preprocessed before applying circular transform. The optic disc diameter and the distance from optic disc to macula are found for a sample of 20 images. An Extreme Learning Machine classifier is used to train the neural network to classify the images as normal or abnormal. Its performance is compared with Support Vector Machine in terms of computation time and accuracy. It is found that computation time is less than 0.1 sec and accuracy is 97.14% for Extreme Learning Machine classifier.
关键词： extreme learning machine,Circular transform,optic disc,segmentation,macula
更新于2025-09-09 09:28:46
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Comprehensive Three-Dimensional Analysis of the Neuroretinal Rim in Glaucoma Using High-Density Spectral-Domain Optical Coherence Tomography Volume Scans
摘要： To describe spectral-domain optical coherence tomography (OCT) methods for quantifying neuroretinal rim tissue in glaucoma and to compare these methods to the traditional retinal nerve fiber layer thickness diagnostic parameter. Neuroretinal rim parameters derived from three-dimensional (3D) volume scans were compared with the two-dimensional (2D) Spectralis retinal nerve fiber layer (RNFL) thickness scans for diagnostic capability. This study analyzed one eye per patient of 104 glaucoma patients and 58 healthy subjects. The shortest distances between the cup surface and the OCT-based disc margin were automatically calculated to determine the thickness and area of the minimum distance band (MDB) neuroretinal rim parameter. Traditional 150-lm reference surface–based rim parameters (volume, area, and thickness) were also calculated. The diagnostic capabilities of these five parameters were compared with RNFL thickness using the area under the receiver operating characteristic (AUROC) curves. The MDB thickness had significantly higher diagnostic capability than the RNFL thickness in the nasal (0.913 vs. 0.818, P ? 0.004) and temporal (0.922 vs. 0.858, P ? 0.026) quadrants and the inferonasal (0.950 vs. 0.897, P ? 0.011) and superonasal (0.933 vs. 0.868, P ? 0.012) sectors. The MDB area and the three neuroretinal rim parameters based on the 150-lm reference surface had diagnostic capabilities similar to RNFL thickness. The 3D MDB thickness had a high diagnostic capability for glaucoma and may be of significant clinical utility. It had higher diagnostic capability than the RNFL thickness in the nasal and temporal quadrants and the inferonasal and superonasal sectors.
关键词： neuroretinal rim,spectral-domain optical coherence tomography,glaucoma,optic disc,optic nerve
更新于2025-09-04 15:30:14