Regulation of intraocular pressure during cyclocryotherapy for advanced glaucoma

Five eyes of five patients with advanced glaucoma were treated with cyclocryotherapy. Intraocular pressure was monitored by applanation tonometry during the procedure and for the first 24 hours postoperatively. Two patients underwent a standard form of treatment, and exhibited two components of acute increases in intraocular pressure as a result of the procedure. Intraoperatively, intraocular pressure increased abruptly to 60 to 80 mm Hg during the freezing phase of cyclocryotherapy and decreased to baseline levels during the thaw phase. Postoperatively, intraocular pressure increased to approximately 50 mm Hg, peaking six hours after the procedure. We devised a method of manometric regulation of intraocular pressure to prevent significant increases during cyclocryotherapy and used it in three patients. This group maintained intraocular pressures of approximately 25 mm Hg intraoperatively, and exhibited blunted postoperative increases. Manometric regulation of intraocular pressure during cyclocryotherapy for advanced glaucoma may protect seriously compromised optic nerves from further damage, and may represent a safer method of treatment.