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Artificial Intelligence and Deep Learning are Changing the Healthcare Industry
Published in Archana Singh, Vinod Kumar Shukla, Ashish Seth, A. Sai Sabitha, ICT and Data Sciences, 2022
Gaurav Singh, Anju Mishra, Archana Singh
Glaucoma is a chronic, neurodegenerative ocular condition that can cause permanent vision loss or blindness by damaging the optic nerve. Usually, there are no symptoms and patients become aware of the disease when considerable damage has already been done. There is no cure for glaucoma but if detected early, vision could be protected from further damage by various treatments and surgeries. Glaucoma is caused when the fluid inside the eyes, known as aqueous humor, starts being collected and thus increases the eye pressure. It happens when the channels responsible for the drainage of the fluid get blocked. As the fluid builds up inside the eye, the interocular pressure (IOP) starts rising and this damages the optic nerve. Once optic nerve cells start dying, there is vision loss. As optic nerve cells don’t have the ability to regenerate, once a large amount of these optic cells die the patient could become blind.
Development of Ophthalmic Formulations
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Paramita Sarkar, Martin Coffey, Mohannad Shawer
Aqueous humor is a clear fluid that is secreted by the ciliary body via the filtration of blood passing through the ciliary body capillaries. It has several functions including maintaining the shape of the eye by controlling its pressure, providing nutrition to the cornea and lens, and providing transport of waste materials away from surrounding tissues. The aqueous humor is composed mainly of water; high concentrations of ascorbic acid, glucose, and amino acids; and limited levels of proteins. Aqueous humor flows from the ciliary body in the posterior chamber (behind the iris) into the anterior chamber (between the iris and the cornea). Aqueous humor flows out of the eye through the trabecular meshwork (a network of collagen fibers and endothelial-like trabecular cells) into Schlemm’s canal and through the uveoscleral route [24]. The entire volume of the aqueous humor is about 0.2 mL and is replaced every 1–2 h [19]. Maintaining the intraocular pressure (IOP) of 10–20 mmHg is a balancing act of production and drainage.
The Mechanobiology of Aqueous Humor Transport across Schlemm's Canal Endothelium
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Intraocular pressure (IOP) is controlled by the turnover of aqueous humor, a clear fluid that fills the anterior segment of the eye and serves to nourish the avascular tissues of the cornea, lens, and trabecular meshwork (Figure 21.1). Aqueous humor is secreted into the posterior chamber by the ciliary processes, enters the anterior chamber through the pupil, and drains through one of two outflow pathways. The conventional or trabecular outflow pathway carries the majority of outflow and includes the trabecular meshwork, Schlemm's canal, and downstream collecting vessels that lead to the episcleral veins. The secondary uveoscleral outflow pathway appears to account for only 3%–35% of total outflow in the human eye (as surveyed by Nilsson [1]) and likely contributes little toward IOP regulation, although uveoscleral outflow does become important for glaucoma therapies involving prostaglandins and its analogues.
Preparation of 5-fluorouracil loaded chitosan microtube via in situ precipitation for glaucoma drainage device application: in vitro and in vivo investigation
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Xia Zhao, Sihao Liu, Yuemei Han, Yuqin Wang, Quankui Lin
Glaucoma, with characteristics of increased intraocular pressure (IOP) and visual field defect, is the leading cause of irreversible vision loss in the world [1]. It is considered that the interruption of the aqueous humor circulation is the origin of glaucoma. When the circulation of the aqueous humor is blocked, the IOP increases, which makes great compression to optic nerve in the retina, thus damaging the visual field. At present, the primary treatment of glaucoma is drug therapy, followed by laser therapy. Surgical treatment including filtering surgery and drainage device implantation will be essential under the condition that the IOP is out of control with the routine treatment. In terms of long-time reduction of IOP, drainage device implantation is superior to filtration surgery [2].
XEN Gel Implant: a new surgical approach in glaucoma
Published in Expert Review of Medical Devices, 2018
Ankita Chaudhary, Lauriane Salinas, Jacopo Guidotti, André Mermoud, Kaweh Mansouri
Trabeculectomy is the most commonly performed incisional surgical procedure to lower IOP. It consists of excision of a small portion of the trabecular meshwork and adjacent corneoscleral tissue to provide a pathway for drainage of aqueous humor from within the eye to under the conjunctiva where it is absorbed. Despite its widespread use, trabeculectomy has its limitations. Apart from the short-term problems like near 50% rate of transient perioperative complications [15], the long-term rate of failure has been reported to be as high as 50% at 5 years, even with adjunctive 5-FU (Fluorouracil) or mitomycin C (MMC), as reported in ‘the tube versus trabeculectomy study’ [16].
Glaucoma Detection Using Optical Coherence Tomography Images: A Systematic Review of Clinical and Automated Studies
Published in IETE Journal of Research, 2022
Hina Raja, Muhammad Usman Akram, Taimur Hassan, Aneeqa Ramzan, Amtual Aziz, Hira Raja
Glaucoma is a group of ocular diseases with several causes that ultimately result in progressive and degenerative optic neuropathy leading to visual field defects [2]. Glaucoma is an eye condition, caused usually by an increase in intraocular pressure leading to optical nerve damages [3]. The ciliary body produces aqueous humor which passes through the pupil and goes into the trabecular mesh. The rate of aqueous humor production and drainage through the trabecular mesh should be the same. In normal eyes, the pressure should be ≤20 mmHg and they show the symptoms of glaucoma if it ranges from 20 to 24 mmHg. However, once intraocular pressure exceeds 24 mmHg, it is diagnosed as glaucoma. If the pressure in the anterior chamber of the eye increases, thus raising the pressure in the posterior chamber that further damages the optic nerve head fibers [9]. Glaucoma is a slow progressive neuropathy; the early stages of the disease do not often show any symptoms. The axon of ganglion cells dies due to glaucoma and results in irreversible vision loss. A normal optic nerve consists of 1.2–1.5 million nerve fibers, approximately. Loss of the axon layer results in the thinning of the nerve fiber layer, thus increasing the cup size this phenomenon is known as cupping. However, the most threatening issue is that a significant nerve fiber layer damage occurs before the visual field defect, which leads to permanent blindness. It was observed that 60% of the patients have significant RNFL loss, approximately six years prior to any detectable defects in the visual field [10,11]. In the early stages of glaucoma, peripheral vision loss occurs, which is difficult to diagnose even by the patient. Figure 1 shows the visual field of normal and different stages of glaucoma patients. An analysis of the RNFL loss is of significant importance for the diagnosis, especially in the early stages of glaucoma. Some individuals are more prone to develop glaucoma than others. These include people who are severely myopic or nearsighted; people who crossed the age of forty; individuals who have diabetes, narrow angles; people diagnosed with low systemic blood pressure, hypertension, long term steroid or cortisone users; people who have high intra ocular pressure and with enlarged optic nerves.