[Comparative study on diode laser (680 nm) and krypton laser mild photocoagulation--histological findings and...

A histopathological study of macaca monkey retina-choroid was carried out for one month after mild photocoagulation with a diode laser (680 nm) and a krypton laser (647 nm). Both lasers produced the same damage to the outer layer of retina and to the melanocytes of 1/3 of the inner choroid. Mild focal photocoagulation was done for 6 patients (12 eyes) with diabetic maculopathy. The patients were 41 to 67 years old, suffering from diabetes mellitus for 5 to 25 years. The grade of their retinopathy was Fukuda's classification AI, AII, and BI. AII eyes were tested before and 3-6 months after photocoagulation for corrected visual acuity, fluorescein angiography, and visual field sensitivity by Octopus automated static perimetry. Visual acuity was stable in all cases. Central sensitivity was better in 2 eyes and unchanged in 4 eyes in both types of laser photocoagulation. In cases of total loss, one eye was improved, 4 eyes were unchanged and one eye was worsened by diode laser photocoagulation and one eye was improved, 2 eyes were unchanged and 3 eyes were worsened by krypton laser photocoagulation. The diode laser (680 nm) might be as useful for ophthalmic laser treatment as the krypton laser.