Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «R»:
Retinal artery, central
Retinal artery, central: The blood vessel that carries blood into the eye and supplies nutrition to the retina.
The counterpart to the central retinal artery is the central retinal vein, the vessel that carries blood away from the retina....
Retinal detachment: A separation of the retina
from its connection at the back of the eye. The separation
usually results from a tear (that is, a rent or rip, not a
tear drop) in the retina. The tear often occurs when the
vitreous gel pulls loose or separates from its attachment
to the retina, ...
Retinal disease: In medicine, called retinopathy.
Retinal electrophysiologic testing
Retinal electrophysiologic testing: See: Electrophysiologic retinal testing ....
Retinal fundus: The interior lining of the eyeball, including the retina (the light-sensitive screen), optic disc (the head of the nerve to the eye), and the macula (the small spot in the retina where vision is keenest). The fundus is the portion of the inner eye that can be seen during an eye exami...
Retinal pigment epithelium
Retinal pigment epithelium: The pigment cell layer that nourishes the retinal cells.
The retinal pigment epithelium is located just outside the retina and is attached to what is called the choroid, a layer filled with blood vessels that nourish the retina....
Retinal vasculitis: The retina is the portion of the eye that contains the nerves of sensation that perceive light. It is also filled with tiny blood vessels. Vasculitis of the eye is typically the result of inflammation of the tiny blood vessels of the retina. This form of vasculitis is referred ...
Retinal vein, central
Retinal vein, central: The blood vessel that carries blood away from the retina of the eye.
The counterpart to the central retinal vein is the central retinal artery, the blood vessel that carries blood into the eye and supplies nutrition to the retina....
Retinal wrinkling: See: Macular pucker....
Retinitis pigmentosa: Any one of a large group of inherited disorders in which abnormalities of the photoreceptors (the rods and cones) in the retina lead to progressive visual loss. People with retinitis pigmentosa (RP) first experience defective dark adaptation ("night blindness"), then constric...
Retinitis pigmentosa and congenital deafness
Retinitis pigmentosa and congenital deafness: (Also called Usher syndrome.) A genetic disorder characterized by hearing impairment and an eye disorder called retinitis pigmentosa in which vision worsens over time. Some people with Usher syndrome also have balance problems.
It is the most common dis...
Retinoblastoma: A malignant eye tumor in children, usually under age 5, that arises in cells in the developing retina containing cancer-predisposing mutations in both copies of the gene RB1. The most common sign of retinoblastoma (RB) is a white pupillary reflex to light (leukocoria). Strabismus (a ...
Retinoic acid syndrome
Retinoic acid syndrome: A syndrome that occurs from treatment with retinoic acid and is characterized by fever, dyspnea (difficulty breathing), chest pain, lung infiltrates evident on chest X-ray, pleural and pericardial effusions (fluid around the lungs and heart) and hypoxia (lack of oxygen).
Retinoid: 1. Vitamin A (retinol) or a naturally occurring or synthetic substance chemically related to it. (Retinoid literally means "like retinol.")
2. In ophthalmology, resembling the retina....
Retinol: Retinol is vitamin A. Carotene compounds (found, for example, in egg yolk, butter and cream) are gradually converted by the body to vitamin A (retinol). A form of vitamin A called retinal is responsible for transmitting light sensation in the retina of the eye. Deficiency of vitamin A lead...