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Systems designed for ophthalmic tissue photocoagulation by applying laser energy simultaneously to multiple spots following a pre-determined pattern. These systems usually consist of one or more dedicated ophthalmic lasers, laser delivery systems that may be an integrated part of the system or attached to a slit lamp or indirect ophthalmoscope, and controls for laser delivery which regulate the size and intensity of the beam on the application spots. The system typically includes one or more lasers whose wavelengths (and frequencies) depend on the pigments in the target tissue (usually the retina) whose components absorb different frequencies of light. Hemoglobin mainly absorbs blue, yellow, and green light; the melanin absorbs yellow, green, red, and infrared light; and the macular tissue mainly absorbs blue light. Consequently, the system includes lasers with one or more of the following wavelengths: (1) green light of 532 nm wavelength (e.g., frequency-doubled Nd:YAG laser) to target melanin; (2) yellow light of 577 nm wavelength (e.g., diode-pumped semiconductor laser) to target hemoglobin; (3) red light of 659 nm wavelength (e.g., diode lasers) for pigmented lesions including melanomas; and (4) infrared light of 810 nm wavelength (e.g., diode lasers) to treat retinovascular edema. The delivery systems are capable of applying one or more of the wavelengths following a great variety of patterns (e.g., rectangular, circular, linear) or only to one point of the eye (usually a spot on the retina).
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