Contact transscleral irradiation of the human chorioretina with continuous-wave Nd:YAG laser.

We performed contact transscleral chorioretinal photocoagulations with a continuous-wave Nd:YAG laser on two human eyes affected by choroidal melanomas. An optical-fiber system without any focalization tip was used to deliver the laser energy by placing the fiber in contact with the sclera in the position corresponding to the chorioretinal area to be photocoagulated. With a power of 4 W and an exposure time of 0.5 s, frank white coagulations were obtained. Histological and ultrastructural examination evidenced that the choroidal pigment and the retinal pigment epithelium were the target structures of the radiation. No substantial alterations of the sclera were noted while a good adhesion between the retina and the pigment epithelium cells was observed. The results obtained show that transscleral contact lasers may be safely used in the treatment of some pathologies of the ocular fundus.