Vitreoretinal surgery with the 193 nm excimer laser

The 193 nm excimer laser is known for its ability to precisely ablate soft biological tissues in the air environment with sub-micron depth control and sub-micron damage zones in the surrounding. The lack of a convenient delivery system and strong absorption of this radiation by biological liquids prevented, until recently, microsurgical applications of this laser. We have constructed special tips that are capable of delivering enough energy for effective removal of soft tissues in a strongly absorbing liquid environment. These tips attach to an articulated arm - based delivery system. This instrument was applied to vitreoretinal membranes removal. The accepted technique for these membranes removal is mechanical peeling and cutting which is associated with strong traction of the retina and this occasionally results in retinal damage. It was demonstrated in this study that the 193 nm excimer laser is capable of safely and precisely cutting and ablating these membranes which enable their removal without exerting any fractional forces on the retina. The effective cutting regime of retina and vitreoretinal membranes occurred at energy fluence of about 250-350 mJ/cm²/pulse with a corresponding cutting depth of 50-150 μm/pulse. The results obtained in this study suggest that this technology could be applicable to a wide variety of intraocular procedures.