Vitamin A deficiency: who is at risk? According to the World Health Organization (WHO), vitamin A deficiency is present when the level of the vitamin in the blood plasma is less than 10 micrograms per decilitre (µg/dl). But even the range before this (between 10 and 20 µg/dl) is considered to be the beginning of … Vitamin A Deficiency: Causes and Consequences
Synonyms retinal tumor What is a retinoblastoma? A retinoblastoma is a tumor of the retina (at the back of the eye). This tumor is genetic, i.e. hereditary. It usually occurs in childhood and is malignant. How common is retinoblastoma? Retinoblastoma is a congenital tumor or it develops in early childhood. It is the most common … Retinoblastoma
How is a retinoblastoma inherited? There are two different types of retinoblastoma. On the one hand the sporadic (occasionally occurring) retinoblastoma, which occurs in 40% of cases. This leads to different changes (mutations) in the affected gene and finally to the formation of a retinoblastoma. This usually occurs only on one side and is not … How is a retinoblastoma inherited? | Retinoblastoma
Argyrie is a discoloration of the skin and mucous membranes that appears gray-bluish or slate gray and is irreversible. Argyriasis is caused by ingestion of silver in the form of metallic silver, silver-containing medications, colloidal silver, silver salts, or silver dust. The disease argyriasis belongs to the dyschromias. What is argyriasis? The discoloration of the … Argyrie: Causes, Symptoms & Treatment
The optic nerve is formed by approximately one million nerve fibers. These nerve fibers are grouped into bundles and meet about 10 to 15 millimeters behind the eyeball with the central artery of the retina and the vein. Together, the vessels then move forward in the interior of the nerves to the optic nerve head … Causes of optic atrophy
Dark adaptation (also: dark adaptation) refers to the adaptation of the eye to darkness. As a result of various adaptation processes, light sensitivity increases in this process. Dark adaptation may be impaired due to congenital or acquired disease. What is dark adaptation? Dark adaptation refers to the adaptation of the eye to darkness. The human … Dark Adaptation: Function, Tasks, Role & Diseases
Introduction Nearly everyone can recognize small black dots, fluff or threads when they look at a white wall, the sky or white paper, which other people present cannot see. These spots in the field of vision move flittingly together with the line of sight. They are called “flying mosquitoes” (Mouches volantes). They are caused by … Vitreous body turbidity
Introduction Retinitis pigmentosa is an umbrella term for a group of diseases of the eye which in their course lead to destruction of the retina (retina). The retina is, so to speak, the visual layer of our eye, the destruction of which leads to loss of vision or blindness. The term “retinitis” is rather misleading, … Retinitis pigmentosa
What forms of retinitis pigmentosa are there? As already mentioned at the beginning, retinitis pigmentosa is basically a collective term for a variety of diseases in which similar processes occur. The classification is sometimes different in different works of technical literature, but basically one can distinguish between three groups of Retinitis pigmentosa: In addition to … What forms of retinitis pigmentosa are there? | Retinitis pigmentosa
Synonyms Red eye in the broadest sense: conjunctivitis, conjunctivitis Definition reddened eyes Red eyes is the leading symptom of conjunctivitis. However, the red eye can also occur in many other eye diseases. The conjunctiva is the primarily affected structure of the eye. It usually appears whitish. Red eyes rarely occur as the sole symptom. In … Red eyes
Synonyms Medical: Intravitreal bleeding Definition vitreous hemorrhage A vitreous hemorrhage is the penetration of blood into the vitreous cavity of the eye. This is located behind the lens of the eye. Depending on the amount of blood entering during a vitreous hemorrhage, it can cause varying degrees of symptoms. At the beginning, the patient notices … Vitreous hemorrhage
Rods are the retinal photoreceptors responsible for light-sensitive monochromatic night vision and peripheral vision. The main concentration of rods is outside the yellow spot (fovea centralis) located centrally on the retina, which is mainly populated with three different types of cones for color and sharp vision during the day and in bright twilight. What are … Rods: Structure, Function & Diseases
