[Development of a new technology of photodynamic destruction of newly formed corneal vessels via local administration of photosensitizers].

The purpose of the study was to perfect the procedure, based on the local administration of photosensitizers (PS) into the lumen of vascular trunks, for photodynamic destruction of newly formed corneal vessels. It was performed on 24 rabbits in which corneal intergrowth of newly formed vessels was induced, by applying nine No. 8.0 silk sutures. The vasculature formed 3 weeks later was represented as 20-35 large vascular trunks. A special microneedle, 200 microm in diameter, was designed for local administration of PS. Surgery was performed, by applying microsurgical techniques under an "Opton" operating microscope. The study showed the basic possibility of inserting the microneedle into the lumen of vascular trunks at the limbus with the subsequent filling of vessels with PS. It was sufficient for photodynamic effects to irradiate the cornea with light from the illumination lamp of an operating microscope throughout the operation (3-5 min). The most effective method for locally using PS involved its successive administration into 7-8 largest vascular trunks (the whole network was filled in by anastomoses in each case). The administration of PS into one large nutrient vessel was less effective due to the rapid flowing-out of PS from the vascular minor branches. Deuteroporphyrin sodium (dimegin) has a high photodynamic effect. The morphological basis of the effect is total endothelial destruction of newly formed vessels. The performed studies have demonstrated that the local administration of PS is as effective as the conventional technology of photodynamic therapy. The procedure is more adaptable to the problems of eye surgery due to the absence of systemic action on the patient's body.