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Scientific Reports Jan 2024One significant ocular symptom of neuro-ophthalmic disorders of the optic disk (OD) is optic disk edema (ODE). The etiologies of ODE are broad, with various symptoms and...
One significant ocular symptom of neuro-ophthalmic disorders of the optic disk (OD) is optic disk edema (ODE). The etiologies of ODE are broad, with various symptoms and effects. Early detection of ODE can prevent potential vision loss and fatal vision problems. The texture of edematous OD significantly differs from the non-edematous OD in retinal images. As a result, techniques that usually work for non-edematous cases may not work well for edematous cases. We propose a fully automatic OD classification of edematous and non-edematous OD on fundus image collections containing a mixture of edematous and non-edematous ODs. The proposed algorithm involved localization, segmentation, and classification of edematous and non-edematous OD. The factorized gradient vector flow (FGVF) was used to segment the ODs. The OD type was classified using a linear support vector machine (SVM) based on 27 features extracted from the vessels, GLCM, color, and intensity line profile. The proposed method was tested on 295 images with 146 edematous cases and 149 non-edematous cases from three datasets. The segmentation achieves an average precision of 88.41%, recall of 89.35%, and F1-Score of 86.53%. The average classification accuracy is 99.40% and outperforms the state-of-the-art method by 3.43%.
Topics: Humans; Optic Disk; Papilledema; Fundus Oculi; Algorithms; Retinal Vessels
PubMed: 38172282
DOI: 10.1038/s41598-023-50908-5 -
Medical & Biological Engineering &... Feb 2022Precise detection of the optic disk (OD) is an important task in the diagnosis of diabetic retinopathy. To manage the massive diabetic population, there is a significant...
Precise detection of the optic disk (OD) is an important task in the diagnosis of diabetic retinopathy. To manage the massive diabetic population, there is a significant demand for efficient and remote retinal imaging techniques. In this regard, the use of handheld mobile cameras attached to a smartphone is a promising approach. However, smartphone retinal images are often of low quality, compared to those obtained on standard equipment. They also have a narrow field of view and an incomplete/unbalanced vessel structure. Hence, we propose a new, fully automatic hybrid method for OD localization (HLM). It is designed for and verified on mobile camera/smartphone retinal images. The HLM analyzes the vessel structure and finds the OD locations by using the exclusion method when an image has a complete vessel system, and a newly proposed line detection method, otherwise. For OD segmentation, an active contour model followed by the circle fitting approach is integrated into the HLM. The proposed method was tested on three mobile camera datasets and four datasets obtained by standard equipment. For mobile camera datasets, the HLM achieves an average accuracy of 98% for OD localization. The segmentation routine obtains an average precision of 92.64% and an average recall of 82.38%. Testing against the recent state-of-the-art methods on the standard datasets shows comparable performance. The proposed framework for OD localization and segmentation designed for and verified on mobile camera retinal datasets and standard datasets. (EM - "Exclusion Method", LDM - "Line Detection Method", OD - "Optic Disk" and PPV - "Positive Predictive Value").
Topics: Algorithms; Cell Phone; Diabetic Retinopathy; Humans; Optic Disk; Retinal Vessels
PubMed: 34988764
DOI: 10.1007/s11517-021-02484-x -
Journal of AAPOS : the Official... Oct 2023Neonatal retinal hemorrhage is a common finding in newborns, but the underlying mechanisms are not fully understood. A computational simulation was designed to study the...
PURPOSE
Neonatal retinal hemorrhage is a common finding in newborns, but the underlying mechanisms are not fully understood. A computational simulation was designed to study the events taking place in the eye and orbit when the head is compressed as the neonate passes through the birth canal.
METHODS
A finite element model of the eye, optic nerve sheath, and orbit was simulated and subjected to forces mimicking rises in intracranial pressure (ICP) associated with maternal contractions during normal vaginal delivery. Resulting changes in intraocular pressure (IOP), pressure in the optic nerve sheath, and stress within the sclera and retina were measured.
RESULTS
During contractions, increased ICP was transmitted to the orbit, globe, and optic nerve sheath. IOP rose by 2.71 kPa near the posterior pole. Pressure at the center of the optic nerve sheath rose by 7.31 kPa and up to 9.30 kPa at its interface with the sclera. Stress in the retina was highest near the optic disk and reached 10.93, 10.99, and 13.28 kPa in the preretinal, intraretinal, and subretinal layers, respectively. Stress in the sclera peaked at 12.76 kPa.
CONCLUSIONS
Increasing ICP associated with natural vaginal delivery increases intraorbital pressure, which applies stress to the retina. Associated retinal deformation may cause tearing of the retinal vasculature. Increased pressure within the optic nerve sheath may occlude the central retinal vein, resulting in outflow obstruction and subsequent rupture. Forces accumulated near the optic disk, likely accounting for the tendency of neonatal retinal hemorrhage to occur posteriorly.
Topics: Female; Humans; Infant, Newborn; Retinal Hemorrhage; Optic Disk; Retina; Intraocular Pressure; Retinal Vessels
PubMed: 37722620
DOI: 10.1016/j.jaapos.2023.07.013 -
Journal of Neuro-ophthalmology : the... Dec 2023
Topics: Humans; Ophthalmologists; Optic Disk; Optic Nerve Diseases; Neurology
PubMed: 37974372
DOI: 10.1097/WNO.0000000000001993 -
Computerized Medical Imaging and... Jan 2021Glaucoma is a disease that affects the optic nerve and can lead to blindness. The cup-to-disc ratio (CDR) measurement is one of the key clinical indicators for glaucoma...
Glaucoma is a disease that affects the optic nerve and can lead to blindness. The cup-to-disc ratio (CDR) measurement is one of the key clinical indicators for glaucoma assessment. However, the CDR only evaluates the relative sizes of the cup and optic disc (OD) via their diameters, and does not characterize local morphological changes that can inform clinicians on early signs of glaucoma. In this work, we propose a novel glaucoma score based on a statistical atlas framework that automatically quantifies the deformations of the OD region induced by glaucoma. A deep-learning approach is first used to segment the optic cup with a dedicated atlas-based data augmentation strategy. The segmented OD region (disc, cup and vessels) is then registered to the statistical OD atlas and the deformation is projected onto the atlas eigenvectors. The atlas glaucoma score (AGS) is then obtained by a linear combination of the principal modes of deformation of the atlas with linear discriminant analysis. The AGS performs better than the CDR on the three datasets used for evaluation, including RIM-ONE and ORIGA650. Compared to the CDR measurement, which yields an area under the ROC curve (AUC) of 91.4% using the expert segmentations, the AGS achieves an AUC of 98.2%. Our novel glaucoma score captures more complex deformations within the optic disc region than the CDR can. Such morphological changes are the first cue of glaucoma onset, before the visual field is affected. The proposed approach can thus significantly improve early detection of glaucoma.
Topics: Diagnostic Techniques, Ophthalmological; Glaucoma; Humans; Optic Disk; Optic Nerve; Risk Assessment
PubMed: 33307282
DOI: 10.1016/j.compmedimag.2020.101797 -
Scientific Data Feb 2023We introduce Chákṣu-a retinal fundus image database for the evaluation of computer-assisted glaucoma prescreening techniques. The database contains 1345 color fundus...
We introduce Chákṣu-a retinal fundus image database for the evaluation of computer-assisted glaucoma prescreening techniques. The database contains 1345 color fundus images acquired using three brands of commercially available fundus cameras. Each image is provided with the outlines for the optic disc (OD) and optic cup (OC) using smooth closed contours and a decision of normal versus glaucomatous by five expert ophthalmologists. In addition, segmentation ground-truths of the OD and OC are provided by fusing the expert annotations using the mean, median, majority, and Simultaneous Truth and Performance Level Estimation (STAPLE) algorithm. The performance indices show that the ground-truth agreement with the experts is the best with STAPLE algorithm, followed by majority, median, and mean. The vertical, horizontal, and area cup-to-disc ratios are provided based on the expert annotations. Image-wise glaucoma decisions are also provided based on majority voting among the experts. Chákṣu is the largest Indian-ethnicity-specific fundus image database with expert annotations and would aid in the development of artificial intelligence based glaucoma diagnostics.
Topics: Humans; Algorithms; Artificial Intelligence; Fundus Oculi; Glaucoma; Optic Disk
PubMed: 36737439
DOI: 10.1038/s41597-023-01943-4 -
International Journal of Computer... Jun 2021The most direct means of glaucoma screening is to use cup-to-disc ratio via colour fundus photography, the first step of which is the precise segmentation of the optic...
PURPOSE
The most direct means of glaucoma screening is to use cup-to-disc ratio via colour fundus photography, the first step of which is the precise segmentation of the optic cup (OC) and optic disc (OD). In recent years, convolution neural networks (CNN) have shown outstanding performance in medical segmentation tasks. However, most CNN-based methods ignore the effect of boundary ambiguity on performance, which leads to low generalization. This paper is dedicated to solving this issue.
METHODS
In this paper, we propose a novel segmentation architecture, called BGA-Net, which introduces an auxiliary boundary branch and adversarial learning to jointly segment OD and OC in a multi-label manner. To generate more accurate results, the generative adversarial network is exploited to encourage boundary and mask predictions to be similar to the ground truth ones.
RESULTS
Experimental results show that our BGA-Net system achieves state-of-the-art OC and OD segmentation performance on three publicly available datasets, i.e., the Dice scores for the optic disc/cup on the Drishti-GS, RIM-ONE-r3 and REFUGE datasets are 0.975/0.898, 0.967/0.872 and 0.951/0.866, respectively.
CONCLUSION
In this work, we not only achieve superior OD and OC segmentation results, but also confirm that the values calculated through the geometric relationship between the former two are highly related to glaucoma.
Topics: Diagnostic Techniques, Ophthalmological; Fundus Oculi; Glaucoma; Humans; Neural Networks, Computer; Optic Disk
PubMed: 33963969
DOI: 10.1007/s11548-021-02373-6 -
Vestnik Oftalmologii 2022The article presents five cases of various forms of hemangiomas of the optic nerve head (ONH) and juxtapapillary retina that were monitored and analyzed using ocular...
The article presents five cases of various forms of hemangiomas of the optic nerve head (ONH) and juxtapapillary retina that were monitored and analyzed using ocular visualization methods. The obtained data allowed a conclusion that capillary hemangioma of the ONH features clearly-seen boundaries of the lesion both on ophthalmoscopy and optical coherence tomography (OCT) images; on the other hand, juxtapapillary granuloma can be characterized by blurred outlines on ophthalmoscopy and a gradual transition of the altered retina on OCT images with secondary changes seen in the macular area. When comorbid, capillary hemangioma of the ONH and retina feature a combination of these visualization signs.
Topics: Hemangioma, Capillary; Humans; Ophthalmoscopy; Optic Disk; Retina; Tomography, Optical Coherence
PubMed: 35488564
DOI: 10.17116/oftalma202213802166 -
The British Journal of Ophthalmology May 2023The vascular supply of the optic nerve head is complex and remains incompletely delineated. Over the past 50 years, various investigators have attempted to clarify the... (Review)
Review
The vascular supply of the optic nerve head is complex and remains incompletely delineated. Over the past 50 years, various investigators have attempted to clarify the relative contributions of the choroid, the short posterior ciliary arteries and the central retinal artery to the vascular beds of the inner retinal, prelaminar, laminar and retrolaminar segments of the nerve head. Conflicting theories have evolved, in no small part due to differing techniques of study, involving both flow parameters and anatomical constructs. These have included studies, both in normal subjects and in those with optic nerve ischaemia, of histopathology, electron microscopic corrosion casting, orbital colour Doppler flow studies, fluorescein angiography, indocyanine green angiography, laser Doppler flow studies, laser speckle flowgraphy, microperfusion and labelling studies and optical coherence tomography angiography. The nature of the optic disc, peripapillary retina and choroid microvasculature has implications for the pathophysiology of ischaemic optic neuropathy.
Topics: Humans; Optic Disk; Retinal Artery; Retina; Fluorescein Angiography; Optic Neuropathy, Ischemic; Ischemia; Tomography, Optical Coherence
PubMed: 36261258
DOI: 10.1136/bjo-2022-322254 -
International Journal of Molecular... Jul 2022Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision... (Review)
Review
Glaucomatous optic neuropathy is the leading cause of irreversible blindness in the world. The chronic disease is characterized by optic nerve degeneration and vision field loss. The reduction of intraocular pressure remains the only proven glaucoma treatment, but it does not prevent further neurodegeneration. There are three major classes of cells in the human optic nerve head (ONH): lamina cribrosa (LC) cells, glial cells, and scleral fibroblasts. These cells provide support for the LC which is essential to maintain healthy retinal ganglion cell (RGC) axons. All these cells demonstrate responses to glaucomatous conditions through extracellular matrix remodeling. Therefore, investigations into alternative therapies that alter the characteristic remodeling response of the ONH to enhance the survival of RGC axons are prevalent. Understanding major remodeling pathways in the ONH may be key to developing targeted therapies that reduce deleterious remodeling.
Topics: Glaucoma; Humans; Intraocular Pressure; Optic Disk; Optic Nerve Diseases; Retinal Ganglion Cells
PubMed: 35897642
DOI: 10.3390/ijms23158068