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What is glaucoma?
Last reviewed: 19.11.2021
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Glaucoma (from the Greek glaukos) - "watery blue". For the first time this term was mentioned in Hippocrates's "Aphorisms" about 400 BC. Over the next few hundred years, it was believed that glaucoma is a disease of the lens. "The scientific history of glaucoma began on the day when the cataracts were given the right place" (Albert Turson, 1867-1935, French ophthalmologist). The determination by the German ophthalmologist in 1894 of the correct anatomical location of the optic nerve in the cat and the subsequent use of these data by Edward Jager (1818-1884) led to the assertion that the optic nerve is involved in the process. In the late 1850's. Edema of the optic nerve as a sign of glaucoma was proved by anatomist Henry Muller. In 1856, von Grefe first described the narrowing of the fields of vision and paracentral defects in glaucoma.
Until recently, it was believed that the presence of glaucoma when intraocular pressure (IOP) exceeded 21 mm Hg should be assumed. (ie, more than 2 standard deviations above the average value of intraocular pressure, according to the population survey). More recent studies have shown that most people with intraocular pressure more than 21 mm Hg. There is no glaucomatous narrowing of the fields of vision. In addition, approximately 40% of people with gla-comatose narrowing of the visual fields never had more than 21 mm Hg in their intraocular pressure. The modern concept of primary open-angle glaucoma is a description of a set of symptoms often found in glaucoma, which include intraocular pressure, the form of the optic disc and the characteristic changes in the visual fields. The key point in the diagnosis of glaucoma is the progressive changes in the optic nerve disk, or the fields of vision, or both at the same time. Many specialists in glaucoma are sure that primary open-angle glaucoma is manifested in many diseases with a common pathogenesis of the final stages. Probably, as the understanding of the disease increases, the definition of glaucoma will be improved.
The most modern definition: glaucoma is a pathological condition with progressive death of axons of ganglion cells, leading to a violation of the visual fields, which is associated with intraocular pressure. Thus, when diagnosing a diagnosis, the following aspects should be evaluated: anamnesis, the presence or absence of risk factors, intraocular pressure, the condition of the optic nerve disc, and examine the visual fields.
A short essay on the physiology of eye moisture and intraocular pressure
Ciliary processes (the pars plicata area of the retina) form the moisture of the eye. Epithelial cells of the inner non-pigmented layer are the place of production of moisture. Moisture is formed as a result of a combination of active secretion, ultrafiltration and diffusion. Many intraocular agents, reducing intraocular pressure, inhibit secretion in the ciliary body. The moisture through the pupil flows into the anterior chamber of the eye, feeding the lens, cornea and iris. Moisture flows through the angle of the anterior chamber, in which the trabecular network and the surface of the ciliary body are located.
Approximately 80-90% of the eye's moisture flows through the trabecular network - the traditional outflow path, the remaining 10-20% through the surface of the ciliary body - the uveoscleral or alternative outflow pathway. The trabecular network is considered to be the place where the regulation of outflow of the intraocular fluid takes place. In the trabecular network, especially in conditions of increased intraocular pressure, the greatest resistance to outflow is possessed by the yukstakanalikulyarnaya region.
[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]
The optic nerve
The optic nerve consists of all axons of cells of the ganglionic layer of the retina. The optic nerve is a structure that is affected by glaucoma. Functionally, damage to the optic nerve leads to a change in the visual fields. In the absence of treatment, increased intraocular pressure can lead to a progressive narrowing of the visual fields and ultimately to blindness.
The value of intraocular pressure
Knowledge of the fundamentals of the physiology of the eye is important for understanding the pathophysiology, diagnosis and treatment of glaucoma. Currently, many doctors and scientists believe that in the pathogenesis of glaucoma involved several factors: apoptosis, impaired blood flow to the optic nerve and, perhaps. Autoimmune reactions. Nevertheless, intraocular pressure is one of the most important risk factors for the development of the disease. In addition, the only way to treat glaucoma, the effectiveness of which is clearly proven, is the reduction of intraocular pressure. Despite an understanding of the physiology of intraocular pressure, it is still not completely clear how the eye regulates intraocular pressure at the cellular and molecular levels. Every year, knowledge in physiological processes increases. Perhaps in the future it will be possible to answer a question that worries many patients: "What is the cause of increased intraocular pressure?"