Many cases of glaucoma are intractable to common surgical and laser procedures, and thus they require ciliodestruction to control intraocular pressure. Transscleral cyclocoagulation with a Ruby and/or Nd:YAG laser has been shown to be the most efficacious ciliodestructive procedure. Thi technique has not gained popularity because of prohibitive equipment costs Also the currently used delivery equipment has several limitations. Improved manufacturing and materials have made optical fiber available which can transmit high power laser light. It should now be possible to develop a hand-held, transscleral laser cycloagulation tool which delivers its energy through optical fiber onto the sclera and which can attach to any Ruby or Nd:YAG laser. This would make the procedure easier, faster, cheaper, and more precise, and thereby promote its popularity.The long term objective is to market an inexpensive, noninvasive tool that will reduce intraocular pressure to normal levels in eyes with intractable glaucoma. The specific aims of Phase I feasibility research are to:1) determine limitations and optimal parameters of high power optical fiber,2) develop efficient launch optics of the laser light into the fiber,3) determine the most effective method for coupling the laser light from the fiber to the eye.National Eye Institute (NEI)