[Morphology of the primary damage caused by the argon-ion laser to the iris of the pigmented rabbit (author's transl)].

The effects of the argon-ion laser upon the iris of the pigmented rabbit were analysed by ultrastructural methods. 1. Apart from the physical parameters of the energy source, the damage strongly depends on the concentration, location, and distribution of the iris pigment. 2. The irradiation of the iris results in the formation of a crater. Depending on the distance of the epicentre of the impact, various degrees of ultrastructural damage are observed. a. The region immediately adjacent to the crater lumen at a revealing distance of 25 microns consists of homogenous collagenous masses, revealing a vacuolar structure. As the only residuals of destroyed cells, melanin granules are observed within the homogenous masses. b. Destruction of the collagen fibrils and their disintegration into subfibrils with elimination of all cell compartments is found in an area ranging from 25 microns to 300 microns from the wall of the crater. c. Damage to the chromatin structure is visible up to a distance of 300 microns to 375 microns from the wall of the crater. 3. Characterised by an invasion of macrophages into the damaged area, the cleaning phase starts 24 h after irradiation. 4. The results of this experiment indicate that because of the great energy dose required for man with the inherent widespread tissue damage and low probability of a lasting iridectomy, the cw argon-ion laser appears to be an unsuitable energy source for clinical iridectomy.