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[IEEE 2018 IEEE International Systems Engineering Symposium (ISSE) - Rome, Italy (2018.10.1-2018.10.3)] 2018 IEEE International Systems Engineering Symposium (ISSE) - Implementation of support tools for the presumptive diagnosis of Glaucoma through identification and processing of medical images of the human eye
摘要： In medicine, the diagnosis of diseases by means of image processing has had great acceptability and credibility, which is why it has been able to explore in depth the theme, taking advantage of mainly which is a non-invasive method within the clinical study. Glaucoma is considered as a group of diseases that damages the optic nerve to the point of causing blindness in the eye, with the disadvantage of in most cases do not exhibit early symptoms. Through this work, the processing biomedical images to locate the parameters considered most relevant within images obtained from the back of the eye to make the determination of the existence or not of Glaucoma, a disease that mainly affects physically the dimensions and proportions of the cup and the optical disc. It gets the value of the reason cup/disc and is additional to the characteristics of the rule ISNT, both parameters considered of great importance in the diagnosis of glaucoma. The results obtained serve as a tool to support the specialist in ophthalmology and optometry in conjunction with a presumptive diagnosis of glaucoma, this way it looks for the early detection and prevention of this disease.
关键词： ISNT,visual field,cup-disc,Glaucoma,nerve fibers,image processing,optic nerve
更新于2025-09-09 09:28:46
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Modeling the Chronic Loss of Optic Nerve Axons and the Effects on the Retinal Nerve Fiber Layer Structure in Primary Disorder of Myelin
摘要： We determined whether the chronic lack of optic nerve myelination and subsequent axon loss is associated with optical coherence tomography (OCT) changes in the retinal nerve fiber layer (RNFL), and whether this models what occurs in multiple sclerosis (MS) and confers its use as a surrogate marker for axon degeneration. Using an animal model of Pelizaeus-Merzbacher disease (shp) bilateral longitudinal measurements of the peripapillary RNFL (spectral-domain OCT), electroretinograms (ERG), and visual evoked potentials (VEP) were performed in affected and control animals from 5 months to 2 years and in individual animals at single time points. Light and electron microscopy of the optic nerve and retina and histomorphometric measurements of the RNFL were compared to OCT data. Of the shp animals, 17% had an average reduction of OCT RNFL thickness on the superior retinal quadrant compared to controls (P < 0.05). Electroretinograms showed normal photopic A- and B-waves but flash VEPs were disorganized in shp animals. Morphologically, the shp retinas and optic nerves revealed significant RNFL thinning (P < 0.001) without retinal ganglion cell (RGC) loss, decrease total and relative retinal axonal area, and loss of optic nerve axons. There was strong positive correlation between OCT and morphometric RNFL thickness measurements (r ? 0.878, P ? 0.004). The loss of optic nerve axons demonstrated in the shp model resulted in moderate thinning of the RNFL confirmed by OCT and histology. These results indicate that OCT-derived RNFL measurement can be a useful surrogate biomarker of optic nerve axon loss and potentially disease progression in demyelinating diseases.
关键词： optic nerve,retina,OCT
更新于2025-09-09 09:28:46
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Peripapillary microvasculature in the retinal nerve fiber layer in glaucoma by optical coherence tomography angiography: focal structural and functional correlations and diagnostic performance
摘要： To quantify peripapillary microvasculature within the retinal nerve fiber layer (RNFL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of perfusion parameters with structural and functional measures, and report diagnostic accuracy of perfusion parameters. Patients and methods: POAG and normal patients underwent 6×6 mm2 optic nerve head scans (Angioplex optical coherence tomography angiography [OCTA]; Cirrus HD-OCT 5000) and Humphrey Field Analyzer II-i 24-2 visual field (VF) testing. Prototype software performed semiautomatic segmentation to create RNFL en face images and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) in the optic nerve head globally and focally. Generalized estimating equations models assessed association of OCTA parameters with VF mean deviation (MD) and RNFL thickness. Results: Thirty-eight POAG and 17 normal eyes were studied. Global VAD, VSD, and VCI were reduced in mild POAG vs normal (P<0.02) and moderate-severe vs mild POAG (P<0.04). Stepwise focal reductions across disease stage were demonstrated for OCTA parameters in the inferior hemisphere (P<0.05); reduction in OCTA parameters in mild POAG vs normal was demonstrated in inferior and superior quadrants (P<0.05). Reduced global VF MD was associated with reduced VAD, VSD, and VCI (P=0.0007, 0.0013, <0.0001; R2=0.449, 0.312, 0.399, respectively), and global RNFL thickness was associated with VAD, VSD, and VCI (P<0.0001; R2=0.499, 0.524, 0.542), superior and inferior hemifield MD were associated with corresponding VAD, VSD, and VCI (P≤0.001; R2 from 0.208 to 0.513). RNFL thickness in all quadrants was associated with corresponding OCTA parameters (P<0.05; R2 from 0.213 to 0.394), except temporal VAD and VCI. Area under curves for VAD, VSD, and VCI demonstrated good diagnostic ability (0.868, 0.855, 0.868; P<0.0001). Conclusion: Glaucomatous eyes showed stepwise reductions in RNFL microcirculation across severity; focal reductions in the inferior hemisphere and inferior and superior quadrants were most significant. OCTA parameters had stronger associations with structural rather than functional measures of glaucoma.
关键词： optic nerve head,segmentation,function,large vessel subtraction,diagnostic accuracy,microcirculation,structure
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Automated Optic Nerve Head Detection Based on Different Retinal Vasculature Segmentation Methods and Mathematical Morphology
摘要： Computer vision and image processing techniques provide important assistance to physicians and relieve their work load in different tasks. In particular, identifying objects of interest such as lesions and anatomical structures from the image is a challenging and iterative process that can be done by using computer vision and image processing approaches in a successful manner. Optic Nerve Head (ONH) detection is a crucial step in retinal image analysis algorithms. The goal of ONH detection is to ?nd and detect other retinal landmarks and lesions and their corresponding diameters, to use as a length reference to measure objects in the retina. The objective of this study is to apply three retinal vessel segmentation methods, Laplacian-of-Gaussian edge detector, Canny edge detector, and Matched ?lter edge detector for detection of the ONH either in the normal fundus images or in the presence of retinal lesions (e.g. diabetic retinopathy). The steps for the segmentation are as following: 1) Smoothing: suppress as much noise as possible, without destroying the true edges, 2) Enhancement: apply a ?lter to enhance the quality of the edges in the image (sharpening), 3) Detection: determine which edge pixels should be discarded as noise and which should be retained by thresholding the edge strength and edge size, 4) Localization: determine the exact location of an edge by edge thinning or linking. To evaluate the accuracy of our proposed method, we compare the output of our proposed method with the ground truth data that collected by ophthalmologists on retinal images belonging to a test set of 120 images. As shown in the results section, by using the Laplacian-of-Gaussian vessel segmentation, our automated algorithm ?nds 18 ONHs in true location for 20 color images in the CHASE-DB database and all images in the DRIVE database. For the Canny vessel segmentation, our automated algorithm ?nds 16 ONHs in true location for 20 images in the CHASE-DB database and 32 out of 40 images in the DRIVE database. And lastly, using matched ?lter in the vessel segmentation, our algorithm ?nds 19 ONHs in true location for 20 images in CHASE-DB database and all images in the DRIVE.
关键词： Laplacian-of-Gaussian edge detector,Diabetic retinopathy,Match ?lter,image processing,Optic Nerve Head,Canny edge detector,retinal blood vessel
更新于2025-09-09 09:28:46
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Clinical relevance of protruded retinal layers in minimum rim width measurement of the optic nerve head
摘要： background/aims Optical coherence tomography (OCT) imaging of the optic nerve head minimum rim width (MRW) has recently been shown to sometimes contain components besides extended retinal nerve fibre layer (RNFL). This study was conducted to determine whether excluding these components, termed protruded retinal layers (PRLs), from MRW increases diagnostic accuracy for detecting glaucoma. Methods In this cross-sectional study, we included 123 patients with glaucoma and 123 normal age-similar controls with OCT imaging of the optic nerve head (24 radial scans) and RNFL (circle scan). When present, PRLs were manually segmented, and adjusted MRW measurements were computed. We compared diagnostic accuracy of adjusted versus unadjusted MRW measurement. We also determined whether adjusted MRW correlates better with RNFL thickness compared with unadjusted MRW. results The median (IQR) visual field mean deviation of patients and controls was ?4.4 (?10.3 to ?2.1) dB and 0.0 (?0.6 to 0.8) dB, respectively. In the 5904 individual B-scans, PRLs were identified less frequently in patients (448, 7.6%) compared with controls (728, 12.3%; p<0.01) and were present most frequently in the temporal sector of both groups. Areas under the receiver operating characteristic curves and sensitivity values at 95% specificity indicated that PRL adjustment did not improve diagnostic accuracy of MRW, globally or temporally. Furthermore, adjusting MRW for PRL did not improve its correlation with RNFL thickness in either group. Conclusion While layers besides the RNFL are sometimes included in OCT measurements of MRW, subtracting these layers does not impact clinical utility.
关键词： minimum rim width,OCT imaging,glaucoma,protruded retinal layers,optic nerve head
更新于2025-09-09 09:28:46
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Total Retinal Blood Flow in a Nonhuman Primate Optic Nerve Transection Model Using Dual-Beam Bidirectional Doppler FD-OCT and Microsphere Method
摘要： PURPOSE. We validated noninvasive Doppler-optical coherence tomography (OCT) blood ?ow measurements against the terminal microsphere method in a surgical induced optic nerve transection nonhuman primate model. METHODS. In 6 nonhuman primates, total retinal blood ?ow (TRBF) was measured with a custom-built dual-beam bidirectional Doppler Fourier Domain (FD)-OCT. Peripapillary retinal nerve ?ber layer thickness (RNFLT) was measured by Spectralis spectral-domain (SD)-OCT. Measurements were performed every 10 to 15 days before and after unilateral optic nerve transection (ONT) until RNFLT was reduced by more than 40% from baseline. Before the animals were killed, TRBF was measured using the microsphere technique. RESULTS. A signi?cant correlation between all arterial and venous Doppler OCT TRBF measurements was found in ONT and contralateral control eyes (both P < 0.01, n ? 6). The Bland-Altman analysis showed a bias of 0.57 in the ONT group and 0.02 in the contralateral control group. Also, excellent agreement was observed between Doppler OCT and microsphere measurements (P < 0.01, r ? 0.976, bias ? 0.54). After ONT, TRBF and RNFLT decreased by (cid:2)51% 6 42% and (cid:2)44% 6 2% (n ? 5), respectively. In the contralateral control eyes, TRBF and RNFLT were unchanged. CONCLUSIONS. Very good accordance was found between TRBF measurements, obtained with dual-beam bidirectional Doppler FD-OCT and the microsphere method. It also was possible to monitor changes over time in TRBF after ONT with Doppler OCT. These ?ndings highlight the accuracy and potential of noninvasive Doppler OCT to provide valuable information for detecting early changes in ocular disease in future.
关键词： microspheres,optic nerve transection,total retinal blood ?ow,Doppler OCT,nonhuman primate
更新于2025-09-09 09:28:46
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Variation in the Three-Dimensional Histomorphometry of the Normal Human Optic Nerve Head With Age and Race: Lamina Cribrosa and Peripapillary Scleral Thickness and Position
摘要： This study quantified the thickness and depth of the lamina cribrosa (LC) and peripapillary scleral thickness in high-resolution three-dimensional (3D) fluorescent reconstructions of the optic nerve head (ONH) in eyes from donors of African (AD) and European descent (ED). A total of 64 eyes (45 ED, 19 AD) from 51 normal donors were obtained within 6 hours of death and fixed at 10 mm Hg of pressure. The optic nerve head was trephined from the globe and digitally reconstructed at 1.5 3 1.5 3 1.5 lm voxel resolution with an automated episcopic fluorescence technique. The load-bearing ONH connective tissue surfaces were manually delineated in 3D using custom software. The lamina cribrosa and peripapillary sclera were significantly thinner in AD eyes adjusting for age and sex (LC was 24 6 11 lm thinner; P ? 0.0350; scleral was 56 6 22 lm thinner; P ? 0.0097). The lamina cribrosa was significantly thinner in females (23 6 11 lm thinner; P ? 0.0425). Age was not significantly associated with any morphologic parameter in the ED group. However, increasing age was associated with an increase in scleral thickness (1.3 lm/year, P ? 0.0499) and an increase in LC depth (2.3 lm/year, P ? 0.0035) in the AD group. The sclera was thickest in the superior and temporal regions while the LC was thinnest superiorly. Substantial sectorial and racial differences in LC and scleral morphology were observed, as well as increasing LC depth and scleral thickness with age in the AD group. Results suggest greater age-related remodeling of the load-bearing ONH connective tissues in eyes from AD individuals that could explain, in part, the greater predilection to glaucomatous injury seen in aged AD populations.
关键词： race,lamina cribrosa,morphometry,optic nerve head
更新于2025-09-09 09:28:46
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Effects of Age, Race, and Ethnicity on the Optic Nerve and Peripapillary Region Using Spectral-Domain OCT 3D Volume Scans
摘要： Purpose: To evaluate the effects of age, race, and ethnicity on the optic nerve and peripapillary retina using spectral-domain optical coherence tomography (SD-OCT) three-dimensional (3D) volume scans in normal subjects. Methods: This is a cross-sectional study performed at a single institution in Boston. All patients received retinal nerve fiber layer (RNFL) scans and an optic nerve 3D volume scan. The SD-OCT software calculated peripapillary RNFL thickness, retinal thickness (RT), and retinal volume (RV). Custom-designed software calculated neuroretinal rim minimum distance band (MDB) thickness and area. Results: There were 272 normal subjects, including 175 whites, 40 blacks, 40 Asians, and 17 Hispanics. Rates of age-related decline were 2.3%, 2.0%, 1.7%, 3.3%, and 4.3% per decade for RNFL, RT, RV, MDB neuroretinal rim thickness, and MDB area, respectively. The RNFL was most affected by racial and ethnic variations, with Asians having thicker global, superior, and inferior RNFL, Hispanics having thicker inferior RNFL, and blacks having thinner temporal RNFL, compared to whites. For MDB thickness and area, Asians had smaller nasal values and blacks had smaller temporal values. Peripapillary RT and RV parameters were not influenced by race and ethnicity. Conclusions: All of the parameters exhibited age-related declines. RNFL, MDB thickness, and MDB area demonstrated racial and ethnic variations, while peripapillary RT and RV did not. Translational Relevance: This study demonstrates that both normal aging and ethnicity affect several novel 3D OCT parameters used to diagnose and monitor glaucoma (i.e., RT, RV, and MDB), and this should be factored in when making clinical decisions based on these parameters.
关键词： aging,age,optic nerve,spectral-domain OCT,race,peripapillary retina,three-dimensional OCT
更新于2025-09-09 09:28:46
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Multi-scale LBP and SVM Classification to Identify Diabetic Retinopathy in Lesions
摘要： Diabetic Retinopathy (DR) is the most common disease induced by the complication of diabetes, causing blindness. In many rural areas, the contributions of ophthalmologists are predicatively less to treat the disease. Detection of lesions in the early stage is a progressive measure to diagnose DR. Initially, a preprocessing method is performed to detect the Optic Nerve Head (ONH) in the lesion. Based on the degree of reflectance in ONH, feature extraction is computed using multi-scale Local Binary Pattern (LBP) algorithm. Here, Gabor convolution is estimated and the structure of ONH is encoded. This extends to a statistical computation in terms of the moment and standard deviation. A Support Vector Machine (SVM) classification is formulated to locate the hemorrhages and exudates and an effective probabilistic multi-label lesion classification is performed to acquire five sets of results representing the diabetic retinopathy: 1) Grade-1 Exudates, 2) Grade-2 Exudates, 3) Micro aneurysms, 4) Hemorrhages, 5) Neovascularization. Finally, the affected area of lesions is used to diagnose the disease.
关键词： statistical computation,Gabor convolution,local binary pattern,optic nerve head,support vector machine
更新于2025-09-09 09:28:46
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Changes in the Blood Flow of the Optic Nerve Head Induced by Different Concentrations of Epinephrine in Intravitreal Infusion During Vitreous Surgery
摘要： PURPOSE. We investigated whether intravitreal infusion solution containing epinephrine affects optic nerve head (ONH) blood ?ow during vitreous surgeries. METHODS. The subjects were 22 patients with epimacular membrane or idiopathic macular hole. During vitreous surgery, ONH blood ?ow was examined before and 10 minutes after intravitreal infusion of solution containing epinephrine, via a laser speckle ?owgraphy (LSFG) technique modi?ed for acquiring measurements in a supine position. Epinephrine concentration was set at 1.0 mg/500 mL (1:500,000) or 0.5 mg/500 mL (1:1,000,000), with each concentration assigned to 11 consecutive patients. Relative pupil diameter, IOP, blood pressure, and pulse rate also were measured. RESULTS. A signi?cant reduction in blood ?ow throughout the ONH was induced by intravitreal infusion of epinephrine at 1:500,000, but not at 1:1,000,000. Blood ?ow in ONH tissue was diminished at both concentrations, while that in vessels of the ONH was not altered signi?cantly by either concentration. Both epinephrine concentrations induced signi?cant pupillary dilatation, but no signi?cant changes in IOP, blood pressure, or pulse rate. CONCLUSIONS. This study suggests that epinephrine, used in combination with intravitreal infusion solution, may decrease ONH blood ?ow during vitreous surgeries, as indicated by measurements obtained via a modi?ed LSFG technique. Attention must be paid to the effects of intravitreal infusion of epinephrine on ocular circulation, particularly ONH blood ?ow.
关键词： laser speckle ?owgraphy,optic nerve head,epinephrine,supine position,blood ?ow,vitreous surgery
更新于2025-09-09 09:28:46