With the recent propagation of laser systems for the treatment of glaucoma, we logically seek to understand the rationale for the application of laser energy to glaucoma filtering procedures. If lasers can provide a better means of controlling open-angle glaucoma than is currently available by the use of medications, topically or orally, or by the currently employed surgical methods, we must then ask-which lasers and techniques are currently employed to utilize this technology? In particular what is the role of laser sclerostomy in treating glaucoma? What are the advantages and disadvantages of the various lasers, procedures, and techniques for treating glaucoma? What information does it provide us for future applications of laser surgery in glaucoma? This article addresses these issues.