ARGON AND LOW-ENERGY, PULSED ND-YAG LASER TRABECULOPLASTY - A PROSPECTIVE, COMPARATIVE CLINICAL AND MORPHOLOGICAL-STUDY

Argon laser trabeculoplasty (ALT; 1.0 W, 0.1. sec, 50 mu m) was perfor med in right eyes, and toff energy, Q-switched Nd:YAG laser trabeculop lasty (Nd:YAGLT; 1.1-4.8 mJ/pulse) in left eyes of 14 patients with pr imary open-angle glaucoma and in one patient with juvenile glaucoma, T he pre-laser-intraocular pressure (IOP) was medically uncontrollable ( IOP > 21 mmHg), The interocular pressure difference varied between 0 a nd 3 mmHg. In 9 patients IOP decreased to less than 22 mmHg (success) in both eyes, No statistically significant difference has been reveale d with paired t-test in the degree of IOP decrease between ALT and NB: YAGLT treated eyes during the 1-18 months' follow-up, Treatment variab les of Nd:YAGLT had no statistically significant effect on the duratio n of the post-laser success with Cox-regression, In 4 patients both tr eatments were ineffective (IOP > 21 mmHg). In 2 patients ALT was succe ssful but Nd:YAGLT was ineffective, In three cases of early bilateral laser failure (IOP > 21 mmHg at the first month visit) trabeculectomy was performed on both eyes in the third post-laser month, Following AL T the uveoscleral meshwork was severely destroyed in the area of the l aser spots, and the surrounding collagen fibres were heat-damaged, The meshwork between the laser spots was covered by a membrane formed by migrating endothelial cells, In the uveoscleral meshwork Nd:YAGLT indu ced severe focal damage surrounded by circumscript shrinkage and scarr ing, The juxtacanalicular tissue remained free of laser induced damage , No endothelial membrane was present, The results suggest that low en ergy, Q-switched Nd:YAGLT may represent an alternative method of glauc oma laser surgery.