In vivo treatment of proliferations in the vitreous body with a holmium: YAG laser

A Holmium:YAG (Ho:YAG) laser assisted vitrectomy system has been developed. In vitro studies on porcine cadaver eyes were performed to determine optimal laser settings taking into account mechanical effects such as bubble formation and collapse and tissue displacements. Optimal laser settings were 60 - 80 mJ at a pulse length of 150 microsecond(s) . Measurements of induced shockwaves and associated effects led to the construction of a specially designed laser vitrectomy endoprobe that incorporates the distal end of a flexible fiber with 365 micrometers core diameter. Intraocular membranes and strands in the vitreous body of five rabbits were induced by injection of mouse fibroblasts. An additional five rabbits without alterations were treated as a control group. Cutting of membranes was possible and efficient at distances larger than 1.5 mm from the retina. Smaller distances partly led to injuries like retinal holes or ruptures that were induced by mechanical effects of the radiation.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.