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(kĕr-ăt′ō-tōm) [″ + tome, incision] Keratome.


(ker-ă-tot′ŏ-mē) [kerato- + -tomy] 1. Incision of the cornea. 2. Removal of the corneal epithelium, typically by scraping.

photorefractive k. A surgical treatment for myopia, hyperopia, and astigmatism in which the corneal epithelium is removed and its supporting tissue reshaped by an ultraviolet laser.

radial k. A surgical treatment for myopia in which bloodless, hairline, radial incisions are made, as by a laser, in the outer perimeter of the cornea where the incisions will not interfere with vision. The incisions allow the cornea to flatten and helps correct the nearsightedness. About two thirds of patients undergoing this procedure will be able to eliminate the use of glasses or contact lenses.


Inflammation of both the cornea and the uveal tract, i.e., of both the cornea and the iris, ciliary body, and choroid. SYN: cyclokeratitis.


(kē′rē-ŏn) [Gr., honeycomb] An inflamed, boggy mass that appears on the scalp of some patients with tinea capitis. It is believed to represent a hypersensitivity reaction to fungal antigens. It may result in a localized area of permanent hair loss.


(kĕr-nik′tĕr-ŭs) [Ger. Kern, core, kernel, nucleus + icterus] A form of jaundice occurring in newborns during the second to eighth day after birth. The basal ganglia and other areas of the brain and spinal cord are infiltrated with bilirubin. The disorder is treated by phototherapy and exchange transfusion to limit neurological damage. Clinical consequences of the disease include cerebral palsy, speech and language processing disorders, and other forms of pediatric developmental delay. SEE: erythroblastosis fetalis; hemolytic disease of the newborn; hyperbilirubinemia; icterus gravis neonatorum; phototherapy.

Kernig sign

(ker′nig) [Vladimir Mikhailovich Kernig, Russian physician, 1840–1917] A sign of meningeal irritation evidenced by reflex contraction and pain in the hamstring muscles, when attempting to extend the leg after flexing the hip.


(kĕr′ō-sēn) A flammable liquid fuel distilled from petroleum. It is used as a solvent as well as a fuel source.

Keshan disease

(kĕ-shon) [Kèshān county, People's Republic of China] A lethal cardiomyopathy caused by inadequate quantities of selenium in the diet.

keto-, ket-

[Formed fm ketone] Prefixes meaning containing a ketone group, e.g., ketoacidosis, ketosis, ketolysis.


(kēt″ō-as″ĭ-dō′sĭs) [ keto- + acidosis] Acidosis due to an excess of ketone bodies. It occurs in individuals who do not produce adequate insulin to sustain normal fat metabolism. Symptoms typically include nausea, vomiting, excessive urination, rapid breathing, and dehydration.


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