The purpose of this symposium on light-coagulation is not to show the superi ority of the argon-laser-coagulation or, on the contrary, of the classical photo coagulation, but rather to see, if possible, which are the respective indications and contraindications for xenon-are-coagulation as well as for argon-laser coagulation. So, for instance, the argon-Iaser-coagulator is perhaps more appropriate to treat the lesions at and around the macula and the optic disc, but for the peripheral lesions of the retina the xenon-arc photocoagulator is surely as effective. For the conservative treatment of...