ENDOSCOPIC ERBIUM-YAG LASER GONIOTOMY - P RECLINICAL RESULTS

Introduction: Endoscopic erbium-YAG laser treatment is a new approach in glaucoma surgery. In contrast to conventional laser systems, the ph otoablative erbium-YAG laser allows microperforations of the trabecula r meshwork without thermal side effects. We report our first preclinic al trials using this new system.Method: We used the Endognost system ( Schwind Co.). The device combines an endoscope and illumination fiber (0.5 mm diameter), laser fiber (0.5 mm) and a irrigation tube in one p robe with a 1.1 mm external diameter. The Endognost system was tested in porcine and enucleated human eyes. All eyes were examined histologi cally. Results: The endoscopic view into the anterior chamber allows f or precise allocation of the laser pulses. Using a single pulse mode w ith 10 mJ a micropuncture of the trabecular meshwork can be achieved w ithout damaging the adjacent tissue. Using multiple pulses or higher e nergy levels leads to damage of the posterior wall of Schlemm's canal and to thermal side effects. Conclusions: Endoscope guided erbium-YAG laser effects on trabecular tissue are comparable to those produced by a 308 nm excimer laser. Therefore, a similar reduction in intraocular pressure can be expected.