Eye diseases. Glaucoma (most important)

Lecture notes, cheat sheets
Free library / Directory / Lecture notes, cheat sheets

Eye diseases. Glaucoma (most important)

Lecture notes, cheat sheets

Table of contents (expand)

45. Glaucoma

Glaucoma is a chronic eye disease that manifests itself as a constant or periodic increase in intraocular pressure, a special form of optic nerve atrophy, and significant changes in the visual field.

Etiopathogenesis and classification. There are primary, secondary and congenital glaucoma. The development of primary glaucoma is influenced by both local and general factors. Local factors include changes in the drainage system and microvessels of the eye, general hereditary predisposition, neuroendocrine and hemodynamic disorders. Before an increase in intraocular pressure, trophic changes occur in the drainage system of the eye, which causes a violation of the circulation of aqueous humor and an increase in ophthalmotonus.

Classifying primary glaucoma, it is necessary to take into account the form and stage of the disease, the level of intraocular pressure and the dynamics of visual functions. The state of the iridocorneal angle of the anterior chamber and the site of violation of the main resistance to the outflow of aqueous humor determines the form of glaucoma. There are open-angle and closed-angle forms of glaucoma.

With open-angle glaucoma, dystrophic changes in trabecular tissue and intratrabecular canals of varying severity occur, as well as blockade of Schlemm's canal. Types of open-angle glaucoma include pigmentary, pseudoexfoliation and glaucoma with low intraocular pressure. In pigmentary open-angle glaucoma, the pigment completely covers the trabecular zone, which leads to impaired outflow of aqueous humor and increased intraocular pressure. Pseudoexfoliative glaucoma results in the deposition of pseudoexfoliation on the posterior surface of the cornea, iris, ciliary body and in the iridocorneal angle of the anterior chamber. Pseudoexfoliative glaucoma is often combined with cataracts. Glaucoma with low intraocular pressure is characterized by typical symptoms of primary glaucoma: changes in the visual field and partial atrophy of the optic nerve with glaucomatous excavation of the optic nerve head. Angle-closure glaucoma is characterized by blockade of the iridocorneal angle of the anterior chamber by the root of the iris, as well as the development of goniosynechia. Glaucoma occurs with pupillary block, shortening of the iridocorneal angle of the anterior chamber, flat iris and vitreolenticular block. With a mixed form of glaucoma, the signs of open-angle and closed-angle glaucoma are combined.

There are four stages of the disease: initial, advanced, advanced and terminal, and at the same time an acute attack of angle-closure glaucoma. The designation of each stage is carried out by a Roman numeral for a brief record of the diagnosis. The staging of glaucoma is determined by the state of the visual field and the optic disc. The initial stage is characterized by the absence of marginal disc excavation and changes in the peripheral boundaries of the visual field. For advanced and far advanced stages of glaucoma, the presence of marginal excavation is characteristic.

Author: Shilnikov L.V.

<< Back: Astigmatism

>> Forward: Clinical picture of glaucoma

We recommend interesting articles Section Lecture notes, cheat sheets:

▪ Microbiology. Lecture notes

▪ Teria of the organization. Crib

▪ History of medicine. Crib

See other articles Section Lecture notes, cheat sheets.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

The existence of an entropy rule for quantum entanglement has been proven 09.05.2024

Quantum mechanics continues to amaze us with its mysterious phenomena and unexpected discoveries. Recently, Bartosz Regula from the RIKEN Center for Quantum Computing and Ludovico Lamy from the University of Amsterdam presented a new discovery that concerns quantum entanglement and its relation to entropy. Quantum entanglement plays an important role in modern quantum information science and technology. However, the complexity of its structure makes understanding and managing it challenging. Regulus and Lamy's discovery shows that quantum entanglement follows an entropy rule similar to that for classical systems. This discovery opens new perspectives in the field of quantum information science and technology, deepening our understanding of quantum entanglement and its connection to thermodynamics. The results of the study indicate the possibility of reversibility of entanglement transformations, which could greatly simplify their use in various quantum technologies. Opening a new rule ... >>

Mini air conditioner Sony Reon Pocket 5 09.05.2024

Summer is a time for relaxation and travel, but often the heat can turn this time into an unbearable torment. Meet a new product from Sony - the Reon Pocket 5 mini-air conditioner, which promises to make summer more comfortable for its users. Sony has introduced a unique device - the Reon Pocket 5 mini-conditioner, which provides body cooling on hot days. With it, users can enjoy coolness anytime, anywhere by simply wearing it around their neck. This mini air conditioner is equipped with automatic adjustment of operating modes, as well as temperature and humidity sensors. Thanks to innovative technologies, Reon Pocket 5 adjusts its operation depending on the user's activity and environmental conditions. Users can easily adjust the temperature using a dedicated mobile app connected via Bluetooth. Additionally, specially designed T-shirts and shorts are available for convenience, to which a mini air conditioner can be attached. The device can oh ... >>

Energy from space for Starship 08.05.2024

Producing solar energy in space is becoming more feasible with the advent of new technologies and the development of space programs. The head of the startup Virtus Solis shared his vision of using SpaceX's Starship to create orbital power plants capable of powering the Earth. Startup Virtus Solis has unveiled an ambitious project to create orbital power plants using SpaceX's Starship. This idea could significantly change the field of solar energy production, making it more accessible and cheaper. The core of the startup's plan is to reduce the cost of launching satellites into space using Starship. This technological breakthrough is expected to make solar energy production in space more competitive with traditional energy sources. Virtual Solis plans to build large photovoltaic panels in orbit, using Starship to deliver the necessary equipment. However, one of the key challenges ... >>

Random news from the Archive

The value of the Casimir torque is measured 07.01.2019

Researchers from the University of Maryland for the first time in the history of science managed to measure the value of the physical effect, the existence of which was predicted 40 years ago and which is called the Casimir torque. When two tiny particles, no larger than one micron in size, are placed very close to each other in a deep vacuum, they are attracted to each other, the effect of this attraction is known as the Casimir effect. The Casimir torque is related to this phenomenon and is caused by the same quantum electromagnetic effects. Under the influence of the Casimir torque, a tiny particle near the surface of a metallic material in a vacuum begins to rotate. But the force created by the Casimir torque is so small that until recently it was very difficult to measure its absolute value.

To carry out the measurements, scientists had to create a complex setup, the sensitive elements of which are liquid crystals, crystals similar to those used in liquid crystal displays. The liquid crystals were located only 10 nanometers away from the surface of a larger solid crystal. The liquid crystal motion recorder was a special polarizing microscope, which can be used to accurately measure the position of the optical axis of liquid crystals.

Liquid crystals are ideal sensors, as they are extremely sensitive to the effects of any external forces, and the fact that they polarize the light passing through them makes it possible to accurately determine their position at any time. A polarizing microscope sees each pixel of liquid crystals as a light or dark dot, depending on the position of the axis of the crystals themselves. And any change in this position leads to a change in the brightness of the pixel, which is instantly recorded by the microscope.

The scientists used several different types of particles and crystals to measure the precise forces generated by Casimir's torque. These forces have been found to be highly dependent on the kind of material the particles are made from, and each material has its own unique "signature" in terms of these forces.

Knowing the exact values of the forces associated with the Casimir effect is important not only from a scientific point of view. The Casimir effect and torque forces can be used to power nano-sized parts and assemblies of tiny machines, which, in turn, can be assemblies of machines and mechanisms of a larger scale. "In traditional machines, torque is generated and transmitted using motors, crankshafts, cardan shafts, etc." - the researchers write, - "The Casimir torque can do all the same things at the nanoscale level."

Other interesting news:

▪ Miniature Redox Flow Power Supply

▪ Smartphone case with built-in cooling

▪ Smart vest for the blind

▪ Algae as food for livestock

▪ Inflatable motorcyclist vest

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Spy stuff. Article selection

▪ article Hey, Moska! know she is strong... Popular expression

▪ article Can animals distinguish colors? Detailed answer

▪ article gas cutter. Job description

▪ article Cable probe on PIC controllers. Encyclopedia of radio electronics and electrical engineering

▪ article Research of electric machines with the help of light-emitting diodes. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews