Glaucoma
Charles Theisler in Adjuvant Medical Care, 2023
Glaucoma is a group of eye conditions that damage the optic nerve, leading to loss of vision or blindness. Glaucoma develops often as a result of abnormally high pressure in the anterior chamber of the eye. However, not every person with increased eye pressure will develop optic nerve damage.1 There are two major types of glaucoma: open angle and closed angle. Open angle is the most common form, accounting for 90% of all cases. At first, open-angle glaucoma has no symptoms. It causes no pain and vision stays normal. Nonetheless, over time and without treatment, increased intraocular pressure damages the optic nerve. In closed-angle glaucoma, drainage canals are blocked so pressure in the eye increases. Individuals with glaucoma gradually lose their peripheral (side) vision. If glaucoma remains untreated, objects to the side and out of the corner of the eye can be missed. In more advanced cases, patients often report that their vision is like looking through a tunnel. Over time, central vision may also decrease until no vision remains.1
Introduction
Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza in Computer-Aided Glaucoma Diagnosis System, 2020
Glaucoma is dangerous as an ocular disease because it is the second-leading cause of blindness with about 60 million glaucomatous cases globally (Lim et al., 2010), and it is responsible for 5.2 million cases of blindness based on (Lim et al., 2012), with more than 90% of the patients unaware of the condition (Zhang et al., 2014). In 2014, the World Health Organization (WHO) reported that 285 million people were estimated to be visually impaired worldwide: 39 million were blind and 246 million had low vision, in which 80% of all visual impairment could be prevented or cured. The WHO also stated that around 90% of the world’s visually impaired people lived in low-income settings (Koprowski, 2014). Clinically, glaucoma is a chronic eye disease that damages the optic nerve progressively as the disease progresses, causing more optic head damage due to loss of peripheral vision and resulting in a gradual loss of vision. Finally, glaucoma is associated with total blindness. Glaucoma must be managed at the early stage to prevent irreversible optic nerve damage. Treatment can prevent progression of the disease. Therefore, early detection of glaucoma is important to prevent blindness.
Targeting the Nervous System
Nathan Keighley in Miraculous Medicines and the Chemistry of Drug Design, 2020
Electronic properties can also be used to stabilise functional groups. In the case of acetylcholine analogues, the methyl ester is converted into a carbamate to give carbachol. The lone pair of electrons on the nitrogen of the NH2 group can be donated into the carbonyl group and therefore reduce its electrophilic character and stabilise the compound against hydrolysis. Carbachol shows good stability to chemical and enzymatic hydrolysis, but does not show selectivity between the two receptor types. Nevertheless, it was a useful treatment for glaucoma, where it could be applied locally, circumventing the issue of receptor selectivity. Glaucoma is caused by pressure building in the eye when the aqueous contents of it cannot be drained properly and can lead to blindness. Agonists cause the muscles in the eye to contract and relieve the blockage and carbachol proved a useful treatment for this condition.
Brimonidine tartrate for the treatment of glaucoma
Published in Expert Opinion on Pharmacotherapy, 2019
Daniel J. Oh, Judy L. Chen, Thasarat S. Vajaranant, Mark S. Dikopf
Glaucoma is agroup of diseases that leads to permanent damage of the optic nerve and vision loss. An estimated 60.5 million people were affected by primary open-angle glaucoma and primary angle-closure glaucoma globally in 2010[1]. This number is projected to be over 110 million by 2040[1]. Although many non-modifiable risk factors for glaucoma have been identified, landmark clinical trials have shown that lowering intraocular pressure (IOP) can help prevent glaucoma or slow its progression. The Ocular Hypertension Treatment Study showed that lowering IOP by 20% via topical medication was effective in reducing the risk of glaucoma in patients with ocular hypertension (OHTN)[2]. The Early Manifest Glaucoma Trial found a one millimeter of mercury (mmHg) reduction in IOP led to a 10% reduced risk of visual field progression in early open-angle glaucoma[3]. The Advanced Glaucoma Intervention Study showed both laser and surgical intervention for lowering IOP had protective effects on visual field progression in patients with advanced glaucomatous disease[4]. These, along with other trials, have established the clinical importance of lowering IOP in glaucoma patients.
Role of mammalian target of rapamycin in regulating HIF-1α and vascular endothelial growth factor signals in glaucoma
Published in Archives of Physiology and Biochemistry, 2021
Jinzi Zhou, Fenghua Chen, Aimin Yan, Xiaobo Xia
Glaucoma is a group of chronic and progressive eye diseases leading to damages to the optic nerve and irreversible vision loss (Casson et al.2012, Mantravadi and Vadhar 2015). Primary open-angle glaucoma is the most common type of glaucoma (Casson et al.2012, Mantravadi and Vadhar 2015). Elevated intraocular pressure (IOP) is one of the most critical risk factors of glaucoma, resulting in retinal ischaemia, optic nerve damage and retinal ganglion cell death (Selles-Navarro et al.1996, Lafuente et al.2002). Although a number of molecular mediators have been reported to be associated with the retinal and optic nerve damages in open-angle glaucoma (Almasieh et al.2012), the underlying pathophysiological mechanisms by which the disease is developed still need to be studied.
Dorzolamide nanoliposome as a long action ophthalmic delivery system in open angle glaucoma and ocular hypertension patients
Published in Drug Development and Industrial Pharmacy, 2018
Maryam Kouchak, Mohammad Malekahmadi, Neda Bavarsad, Amal Saki Malehi, Laleh Andishmand
Ocular hypertension means the intraocular pressure (IOP) is higher than normal. If left untreated, high eye pressure can cause glaucoma. Glaucoma is a progressive optic neuropathy in which increased IOP leads to the damage of the optic nerve. This disorder can eventually lead to blindness in the affected eye. So this is the major cause of irreversible blindness worldwide after diabetes mellitus [1]. The goal of the treatment is to prevent additional optic nerve damage. Beta adrenoreceptor antagonists and prostaglandin analogs are used as first line treatment of open angle glaucoma. Alpha 2 adrenoceptor agonists and carbonic anhydrase inhibitors (CAIs) are used as second line options [2]. Dorzolamide as a CAIs decreases aqueous humor secretion which result to decrease the IOP [3]. Dorzolamide 2% eye drops has shown the highest clinical effect in studies and an increase in concentration beyond this has no additional clinical effects [4]. Treatments of glaucoma include drug therapy, laser, and surgery. Topical dosage forms such as eye drops are the first choice of treatment [5].
Related Knowledge Centers
- Blurred Vision
- Intraocular Pressure
- Optic Nerve
- Trabecular Meshwork
- Visual Impairment
- Nausea
- Aqueous Humour
- Eye Strain
- Glaucoma Medication
- Laser Coagulation