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Clinical Examination in Neuro-Ophthalmology
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Selvakumar Ambika, Krishnakumar Padmalakshmi
The swinging flashlight test is used to test relative afferent pupillary defect (RAPD) and requires only one working pupil. In unilateral optic nerve diseases, RAPD is usually present. It may be present in bilateral cases if there is asymmetric involvement of optic nerves. Apart from optic neuropathy, RAPD can be present in severe vision loss like retinal detachment, dense amblyopia, ischemic retinal diseases, etc. Measurement of RAPD can be done using neutral density filters by 0.3 log units. Grades of RAPD are described in Table 1.2B.3,4
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
In our nation, diagnosis of disease severity is done generally by the expertise and experienced doctors, but still, there are situations of incorrect diagnosis and treatment are being reported. Patients have to undergo several tests that are very costly and occasionally all of them are not necessary but are forced needlessly into patients to increase the bill. Glaucoma is one of the optic nerve diseases reasoned due to a rise in intraocular pressure and affects the capacity of human vision. Due to a lack of detailed information, each fundus image takes an expert eight minutes to annotate. Glaucoma is the second most common cause of vision loss after cataracts. Quigley et al [1] reported that around 60 million patients were diagnosed worldwide in 2010 and it is estimated that 80 million individuals would be affected by glaucoma by 2020. Glaucoma can cause irreversible damage to the optic nerve, leading to blindness if it is not correctly diagnosed. As a result, early detection of glaucoma is critical for the management of the disease's first-line remedial treatment. Figure 13.1 gives the details of eye image with normal and glaucoma. It also represents the optic cup and disc areas. The clarity of vision of a particular scenario is represented both without glaucoma and glaucoma is depicted in Figure 13.1. The Glaucoma detected eye focuses only on the center part and boundaries are darkened.
Retinal stem cell research
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Henry Klassen, Michael J Young, Robert Ritch, Julia E Richards, Teresa Borrάs, Leonard A Levin
Current treatment strategies for retinal disease, such as laser photocoagulation and vitreoretinal surgical techniques, have revolutionized clinical practice in this area. Nevertheless, there remains no effective treatment for the loss of retinal neurons, particularly photoreceptors and retinal ganglion cells. Retinal and optic nerve diseases are now the major causes of permanent visual disability in the developed world, emphasizing the need to search for restorative treatments for these conditions. Among the most promising new approaches is stem cell transplantation. A basic definition of ‘stem cell’ is a cell that is capable of both renewing itself and giving rise to multiple mature cell types (multipotency). Many cells of interest do not fit the precise definition of a stem cell, and, except in the case of embryonic stem (ES) cells, the term ‘progenitor cell’ is generally preferred. Fortunately, research has not been derailed by semantics. There are many scenarios in which a cell other than an ES cell will likely constitute the cell of choice for transplantation, either alone or as a component of a stem cell graft.
Understanding intrinsic survival and regenerative pathways through in vivo and in vitro studies: implications for optic nerve regeneration
Published in Expert Review of Ophthalmology, 2021
Retinal and optic nerve diseases accompanied by optic nerve degeneration such as optic neuropathy, glaucoma, retinitis pigmentosa, and diabetic retinopathy, cause a severe permanent reduction of vision. The permanence is present because the retinal ganglion cell (RGC) axons cannot regenerate after damage under physiological conditions. At present, two major reasons have been considered that depress the factors involved in optic nerve regeneration; first, a loss of the intrinsic survival and regenerative abilities, and second the presence of an inhibitory glial environment against optic nerve regeneration in the central nervous system (CNS) [1]. Thus, multiple strategies including increasing the intrinsic survival and regenerative abilities and overcoming the inhibitory glial environments are required for successful optic nerve regeneration (Figure 1).
Static and dynamic pupil characteristics in pseudoexfoliation syndrome and glaucoma
Published in Clinical and Experimental Optometry, 2020
Kemal Tekin, Hasan Kiziltoprak, Mehmet Ali Sekeroglu, Esat Yetkin, Serdar Bayraktar, Pelin Yilmazbas
Glaucoma is an optic neuropathy characterised by progressive and chronic loss of retinal ganglion cells and their axons. Analysis of pupillary light reflex is one way to assess the integrity of afferent visual pathways and abnormalities in pupillary light reflex usually present as a relative afferent pupillary defect.1995 The relative afferent pupillary defect might be observed in the conditions of asymmetrical retinal or optic nerve diseases including glaucoma. Measurement of pupillary response via infrared pupillography was introduced by Lowenstein and Loewenfeld,1958 and the recent developments in automated pupillometry devices have enabled quantitative, objective, non‐invasive, and repeatable measurements of pupil diameter in addition to the pupillary kinetics.2018 Various studies have shown that primary open‐angle glaucoma is associated with impairments in pupillary responses by using automated pupillometry.2011 It is also well known that pupillary changes such as poor mydriasis, due to the iris infiltration and fibrosis, are associated with PES.
Neuroprotection of Transplanting Human Umbilical Cord Mesenchymal Stem Cells in a Microbead Induced Ocular Hypertension Rat Model
Published in Current Eye Research, 2018
Shangli Ji, Saiyue Lin, Jiansu Chen, Xinping Huang, Chih-Chang Wei, Zhiyuan Li, Shibo Tang
Glaucoma is a widespread optic neuropathy, characterized by the progressive degeneration of retinal ganglion cells (RGCs) as well as their axons. Glaucoma is a leading cause of irreversible blindness throughout the world, where it has been reported that approximately 111.8 million humans will be affected by glaucoma in 2040.1 The universal risk factor is elevated intraocular pressure (IOP). Current therapies, such as topical eye drops, laser treatment, and surgeries2 directly decrease the IOP, but these treatments do not halt disease progression. It is important to develop novel and effective therapies to prevent or delay progressive optic neuropathy in glaucoma. Mesenchymal stem cell (MSC) transplantation was developed as a promising alternative approach for the treatment of several retina degenerative diseases both in animal models and clinical trials.3,4 Umbilical cord mesenchymal stem cells (UC-MSCs) have strong advantages over other MSC types, since they cause less ethical controversy and are collected easily and noninvasively. UC-MSCs are available in large quantities, have an increased proliferation rate, higher differentiation potential, stronger immunomodulatory capacity, and are more primitive than other adult tissue derived MSCs.5–7 These findings have implications for the development of novel treatments for retina and optic nerve diseases.