Lasers in the treatment of chronic simple glaucoma.

Basic biological effects of laser irradiation are given with respect to the treatment of chronic simple glaucoma. As for the irradiation of the trabecular meshwork, an ultrastructural analysis of what is happening in the method of Wise and Witter (1979) has been done (a). In comparison with the effect of an Argon-ion laser (pulse duration 0.2 s, pulse power 2.2 W) upon the trabecular meshwork of human autopsy eyes the effect of a Nd:YAG laser (pulse duration 10 ms, pulse energy 2 J) has been analysed in ultrastructure. After cyclodialysis by Q-switched laser pulses the routes of outflow of the aqueous humour from the suprachoroidal and supraciliary space have been marked using mercury sulfide red (b). Three ways of outflow could be identified: (1) Into the veins of the ciliary body (2) Into the vortex veins (3) Into the subarachnoidal space around the optic nerve. The last way represents a communication between the suprachoroidal space and the cerebrospinal fluid.