This study substantiates the theory that effective long-term laser treatment for glaucoma is possible in those patients with chronic non-obstructive phakic glaucoma. A common mechanism of glaucoma in these cases would appear to be some type of trabecular collapse. Correction of this trabecular defect may be accomplished with multiple small low-intensity argon laser burns symmetrically placed in the entire circumference of the meshwork. Conversely our histological data indicate that high-intensity burns result in the development of heavy fibrous tissue proliferating within the trabecular meshwork and Schlemm's canal which would appear to contribute to further filtration resistance.