Photocoagulation

The coagulation (clotting) of tissue using a laser which produces light in the visible green wavelength that is selectively absorbed by hemoglobin, the pigment in red blood cells, in order to seal off bleeding blood vessels. Photocoagulation has diverse uses such as, for example, in cancer treatment to destroy blood vessels entering a tumor and deprive it of nutrients; in the treatment of a detached retina; to destroy abnormal blood vessels in the retina; to treat tumors in the eye; etc.

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A method by which a beam of electromagnetic energy is directed to a desired tissue under visual control; localized coagulation results from absorption of light energy and its conversion to heat or conversion of tissue to plasma (atoms stripped of electrons). [photo- + L. coagulo, pp. -atus, to curdle]

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pho·to·co·ag·u·la·tion -kō-.ag-yə-'lā-shən n a surgical process of coagulating tissue by means of a precisely oriented high-energy light source (as a laser beam)

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n.

the destruction of tissue by heat released from the absorption of light shone on it. In eye disorders the technique is used to destroy diseased retinal tissue, occurring, for example, as a complication of diabetes (diabetic retinopathy) and macular degeneration; and to produce scarring between the retina and choroid, thus binding them together, in cases of retinal detachment. Photocoagulation of the retina is usually done with an argon laser or diode laser.

Photocoagulation is also a method of arresting bleeding by causing coagulation, usually using an infrared light source.

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pho·to·co·ag·u·la·tion (fo″to-ko-ag″u-laґshən) [photo- + coagulation] condensation of protein material by the controlled use of an intense beam of light (such as from a xenon arc lamp or argon laser); used especially in treatment of retinal detachment and destruction of abnormal retinal vessels, or of intraocular tumor masses.