Phot: From 1 Different Sources
(photo-) combining form denoting light.
Coagulation of the tissues of the retina (see EYE) by laser, for treatment of diseases of the retina such as diabetic retinopathy (see under EYE, DISORDERS OF – Retina, disorders of).... photocoagulation
Sensitivity to light. It can occur in MIGRAINE, disorders of the eye, or in MENINGITIS.... photophobia
Abnormal reaction to sunlight. The condition usually occurs as a skin rash appearing in response to light falling on the skin, and it may be caused by substances that have been eaten or applied to the skin. These are called photosensitisers and may be dyes, chemicals in soaps, or drugs. Sometimes plants act as photosensitisers – for example, buttercups and mustard. The condition may occur in some illnesses such as lupus erythematosus (see under LUPUS).... photosensitivity
A form of treatment in which deliberate exposure to a photosensitising drug and ultraviolet light bene?ts certain skin diseases, particularly PSORIASIS and T-cell LYMPHOMA. A psoralen is the photoactive agent which reacts with long-wave ultraviolet light (UVA), giving the acronym, PUVA therapy.... photochemotherapy
This comprises a photosensitising agent (one activated by light), which accumulates in malignant tissue, and a source of light that activates the photosensitiser, triggering it to generate highly reactive oxygen compounds that destroy malignant cells. One such photosensitiser is temopor?n. Photodynamic therapy is used to treat various types of malignancy; a recognised complication is photosensitivity, when a patient may suffer burns after transient exposure to sunlight. Photodynamic therapy is increasingly used and photosensitivity reactions may also become more common.... photodynamic therapy
This is a description of the ?ashing lights which are a not uncommon AURA preceding an attack of MIGRAINE.... photopsia
The method by which green plants and some bacteria produce CARBOHYDRATE from water and carbon dioxide. They use energy absorbed from the sun’s rays by a green pigment in the organism called chlorophyll. Photosynthesis is one of the earth’s fundamental biological processes. As well as converting the carbon dioxide into the essential biological compound carbohydrate, the process removes the gas from the atmosphere where, if it builds to excess, the atmospheric temperature rises, thus contributing to global warming.... photosynthesis
A surgical treatment for astigmatism, myopia, and hypermetropia, in which areas of the cornea are shaved away by laser.... photorefractive keratectomy
(American) A stylish woman Photeena, Photeana, Photiena, Photeina, Photyna... photina
Reacting poorly to sunlight, either by skin reactivity or by forming abnormal sunlight-mediated serum metabolites... photosensitive
n. pain in the eye caused by very bright light.... photalgia
n. the use of light or lasers to destroy tissue.... photoablation
n. any of various skin diseases caused by exposure to light of varying wavelength (see photosensitivity). The facial prominences and the ‘V’ of the neck are most commonly affected, the shadow areas behind the ears and below the chin being protected. A common photodermatosis is polymorphous light eruption, which affects 10% of the population. It appears with the first sunshine of spring and abates by late summer. The photodermatoses include certain *porphyrias, notably porphyria cutanea tarda.... photodermatosis
a technique for improving the sensitivity and specificity of bladder cancer diagnosis at cystoscopy using a light-sensitive agent. This agent is instilled into the bladder, taken up by the epithelial cells, and converted into a porphyrin that accumulates only in malignant and premalignant cells. It fluoresces under light of a specific wavelength and is thus highlighted against normal bladder mucosa.... photodynamic diagnosis
n. an enlarged photographic record of an object taken through an optical or electron microscope. Compare microphotograph.... photomicrograph
an electronic device that magnifies the light emitted from a *scintillator by accelerating electrons in a high-voltage field. The resulting signal can be used to display the scintillations on a TV screen. Such devices are commonly used in *gamma cameras.... photomultiplier tube
n. inflammation of the eye due to exposure to light. It is usually caused by the damaging effect of ultraviolet light on the cornea, for example in snow blindness or when lying under a sunbed.... photophthalmia
adj. relating to or describing conditions of bright illumination. For example, photopic vision is vision in bright light, in which the *cones of the retina are responsible for visual sensation. —photopia n.... photopic
n. see photodynamic therapy.... photoradiation
n. damage to the retina of the eye caused by looking at the sun without adequate protection for the eyes. The retina may be burnt by the intense light focused on it; this affects the central part of the visual field, which may be permanently lost (sun blindness).... photoretinitis
(PVP) a technique to vaporize the prostate by means of a high-energy laser, used to relieve *lower urinary tract symptoms due to benign prostatic hyperplasia (see prostate gland). It is associated with less blood loss and a shorter hospital stay than a traditional TURP (see resection), but can only be used on smaller prostates.... photoselective vaporization of the prostate
n. movement of a cell or organism in response to a stimulus of light.... phototaxis
see keratectomy.... phototherapeutic keratectomy
n. damage caused by prolonged exposure to light; for example, retinal phototoxicity is damage to the retina of the eye as a result of prolonged exposure to light.... phototoxicity
n. the excretion of phosphorescent urine, which glows in the dark, due to the presence of certain phosphorus-containing compounds derived from phosphates.... photuria
see SPECT scanning.... single photon emission computed tomography
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