Histopathology of krypton red laser panretinal photocoagulation. A clinicopathologic correlation

The histopathologic appearance of five-day-old and 14-day-old krypton red laser-created panretinal photocoagulation lesions in the diabetic human eye is described. The five-day-old lesions were examined near the equator. The 14-day-old lesions were near the temporal arcades and optic disc. Both groups of laser lesions showed a similar degree of damage and occlusion in the lamina choriocapillaris and deeper choroidal vessels. The 14-day-old posterior laser lesions showed outer retinal damage, whereas the five-day-old peripheral lesions showed full-thickness retinal involvement, probably because the peripheral retina is approximately half the thickness of the posterior retina. The five-day-old lesions showed no evidence of repair, whereas the 14-day-old lesions showed an adhesion formed with tight junctions binding Müller's fibers to retinal pigment epithelium.