Abstract
Abstract: :
Purpose: Excimer Laser Trabeculotomy (ELT) aims to be a minimal invasive method for the reduction of the major amount of outflow resistance, by ablating the anterior juxta-canalicular trabecular meshwork (TM). The success of the perforation is determined by both, laser energy and pressure applied onto the TM by the laser tip in contact. Here we describe the influence of the laser energy when pressure remains constant. Methods: ELT was performed with an Excimer laser (AIDA, GLAUTEC AG, Nuremberg; Germany), wavelength was 308 nm and repetition rate was up to 20 Hz. 20 pulses were applied to each test location with a energy of 1.2mJ, 0.9mJ und 0.6mJ. Laser tip was brought in contact onto the TM under microscopic control and fixated while the ablation. Studies were performed on five human eyes all of which were divided in 4 quadrants. Each quadrant was investigated by serial sections ( 5 micron ). Results: At 1.2 mJ the TM perforated and thermal damage was visible at the outside wall of Schlemm`s canal. At 0.9 mJ the TM was not fully ablated with significant thermal damage. At 0.6 mJ no significant ablation was seen without thermal damage. Conclusion: Our results suggest that an energy of 1.2 mJ is sufficient to penetrate the TM with little collateral damage. However constant pressure applied to the TM is a prerequisite for this result. Therefore control of the pressure is a future goal.
Keywords: 454 laser • 503 outflow: trabecular meshwork