Photocoagulation of the choroid and retina can be produced by the absorption of light energy from either the xenon-arc or the laser photocoagulator. Both coagulator systems deliver light energy in the visible or infrared region of the spectrum, and the ultimate chorioretinal effect is determined by the total amount of light energy absorbed and converted to heat. The major physical difference between the light and laser systems is the type of radiation developed by each method.
The ruby laser beam delivers light energy at one wavelength (6943 A) in the deep red region of the visible spectrum. The effect on an ocular tissue is determined by the specific tissue absorption for that wavelength only and by the instantaneous (0.0005 seconds) intensity of the beam. The xenonarc high pressure bulb delivers radiation from all portions of the visible and near infrared spectrum (Fig). This broad spectral energy output is presented to
L'ESPERANCE FA. Clinical Comparison of Xenon-Arc and Laser Photocoagulation of Retinal Lesions. Arch Ophthalmol. 1966;75(1):61-67. doi:10.1001/archopht.1966.00970050063012