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Dual Customized U-Net-based Automated Diagnosis of Glaucoma
Published in K. Gayathri Devi, Kishore Balasubramanian, Le Anh Ngoc, Machine Learning and Deep Learning Techniques for Medical Science, 2022
C. Thirumarai Selvi, J. Amudha, R. Sudhakar
The CDR (Cup to Disc Ratio) value is calculated using the optic disc and optic cup diameters discovered by computing the diameters of the segmentation masks provided by our suggested method. Vertical diameters and horizontal diameters of the cup and disc are used to generate the vertical and horizontal CDR. The mean value of the vertical and horizontal CDR is computed and if this value is less than 0.5, it means that the person whose retinal fundus image generated this CDR is not having glaucoma. If CDR is greater than 0.5, then the person is suffering from glaucoma. The final glaucoma results of a few of the test set images are given in Table 13.9. The severity of glaucoma is diagnosed as Yes and its absence is diagnosed as No in the tabulated results.
Related Works
Published in Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza, Computer-Aided Glaucoma Diagnosis System, 2020
Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza
Jun et al. (2013) proposed optic disc and optic cup segmentation using superpixel classification for glaucoma detection. In optic disc segmentation they used histograms, and centered surround statistics to classify each superpixel as disc or non-disc. For optic cup segmentation, they used the histograms, center surround statistics, and the location information used as feature space to improve the performance. The proposed segmentation methods have been tested on 650 images with optic disc and optic cup boundaries manually marked as a ground truth. Experimental results obtained an overlapping error of 9.5% and 24.1% in optic disc and optic cup segmentation, respectively. The segmented optic disc and optic cup are then used to compute the cup-to-disc ratio for glaucoma detection, and achieved areas under curve of 0.800 and 0.822 in two data sets. Thus, this method can be used for segmentation and glaucoma detection, and the self-assessment can be used as an indicator of cases with large errors, enhancing the clinical deployment of automatic segmentation and detection.
Ophthalmology
Published in Stephan Strobel, Lewis Spitz, Stephen D. Marks, Great Ormond Street Handbook of Paediatrics, 2019
Most normal cups have a cup to disc ratio of 0.3 or less. Physiological cupping (a cup to disc ratio greater than 0.7) is present in about 2% of the normal population, and glaucomatous cupping (Fig. 7.56), where there is raised intraocular pressure, with or without increased corneal diameter, increased myopia, Haab’s striae and increased axial length.
Findings from a Rapid Assessment of Avoidable Blindness (RAAB) in the Southwest Region of Kyrgyzstan
Published in Ophthalmic Epidemiology, 2020
Brigitte Mueller, Sabina Ibraimova, Elzat Mamutalieva, Hans Limburg, Aigul Ibraimova, Ala Paduca
Visual acuity (VA) was measured using tumbling E-charts with Snellen optotypes size 6/12, 6/18 and 6/60, at 6 or 3 (6/60 only) meters distance. All measurements were taken in full daylight with available spectacle correction. If VA was <6/12 in either eye, then pinhole vision was also measured. A simple ocular examination was performed on every participant in a dark or shaded area. This included an undilated assessment of the lens using a direct ophthalmoscope. When the examined eye did not improve to 6/18 or better with pinhole examination, then the lens was dilated using mydriatic drops for further examination. Cataract was assessed according to the crystalline lens opacity. Glaucoma was defined as the principal cause of visual impairment if the optic cup-to-disc ratio was greater than 0.8, in the absence of another cause of reduced vision. For ARMD, the central retina was examined for swelling or oedema; the macula was examined for the presence of drusen, hypo- or hyper-pigmentation and neovascular changes. Any other pathologies of the retina or vitreous, e.g., retinal detachments or vitreous hemorrhages, were also noted. The principal cause of blindness or visual impairment was recorded according to WHO standards.
Occurrence of MYOC and CYP1B1 variants in juvenile open angle glaucoma Brazilian patients
Published in Ophthalmic Genetics, 2018
Paulo Vinicius Svidnicki, Carolina Ayumi Braghini, Vital Paulino Costa, Rui Barroso Schimiti, José Paulo Cabral de Vasconcellos, Mônica Barbosa de Melo
All the affected and non-affected subjects underwent interview, chart review, and clinical examination to verify individual and family history of glaucoma and/or blindness, age at diagnosis of glaucoma, clinical and surgical treatment, visual acuity, IOP measurement, biomicroscopy and gonioscopy, evaluation of the optic nerve head, and automated perimetry. JOAG was defined in patients diagnosed under 40 years old who showed at least two of the following characteristics: (i) IOP higher than 21 mmHg; (ii) glaucomatous optic disc damage, defined when at least two of the following characteristics were observed: thinning of the neuroretinal rim, hemorrhage, notch, cup-to-disc ratio (CDR) > 0.7, or CDR asymmetry > 0.2; (iii) glaucomatous visual field defect, defined as a pattern standard deviation outside the 95% normal limits or a glaucoma hemifield test outside the 99% limits; (iv) open angle with normal appearance (no goniodysgenesis) on gonioscopy evaluation. PCG was excluded based on corneal findings, such as Haab striae or a diameter >13 mm. Patients with any sign of secondary or developmental glaucoma were excluded. Individuals aged above 50 years with IOPs lower than 16 mmHg, CDR < 0.4, and no family history of glaucoma or blindness of unknown etiology composed the control group.
Dolichoectasia of the internal carotid artery: a report of two cases masquerading as glaucoma
Published in Clinical and Experimental Optometry, 2018
Magdalena Edington, Thomas Siempis, Donald Montgomery, Prem Venkatesh
Despite the fact that the most common cause of optic disc cupping is glaucoma, there are other causes of optic disc cupping which are infrequent and inconsistent in their presentation.2006 Arteritic anterior optic ischaemic neuropathy, once established, can cause pathological disc cupping.2001 Disc cupping is far less common in non‐artertic optic ischaemic neuropathy2001 and posterior ischaemic optic neuropathy, wherein disc pallor is the main feature.2004 Literature supports that compressive optic neuropathy can be associated with increased cupping of the optic disc in the absence of increased IOP.1995 Other causes of optic disc cupping include optic neuritis, where cup‐to‐disc ratio (measured clinically and with OCT) is significantly increased in the affected eye and the retinal nerve fibre layer (RNFL) thickness has been found to be significantly lower compared to the fellow unaffected eye on OCT analysis.2009 Uncommon causes of optic disc cupping are methanol toxicity,2006 dominant optic atrophy2001 and Leber's hereditary optic atrophy in later stages.2004