Comparison of krypton and argon laser photocoagulation. Results of stimulated clinical treatment of primate retina.

We compared the clinical and histological effects of argon blue-green laser (ABGL), argon green laser (AGL), and krypton red laser (KRL) photocoagulation on the primate retina. Burns were produced in juxtafoveal and papillomacular bundle and in nonmacular areas in a manner simulating treatment of a choroidal neovascular membrane (NVM). In the juxtafoveal and papillomacular bundle areas, ABGL photocoagulation caused extensive inner retinal damage while KRL photocoagulation spared inner retinal structures. The effects of AGL photocoagulation in the fovea were intermediate in extent between KRL and ABGL photocoagulation. Axonal transport studies also showed differential effects of these wavelengths on retinal ganglion cell function. Nonmacular effects were similar for all three modalities. These results suggest that the krypton red wavelength may be more suitable than the argon green or argon blue-green wavelengths in treating choroidal NVMs near the fovea.