[Internal sclerostomy with a high-powered argon laser]

A full-thickness sclerostomy from the anterior chamber to the subconjunctival space was created in 9 eyes of 7 rhesus monkeys using an argon endolaser. After the injection of sodium hyaluronate into the subconjunctival space and the anterior chamber, a 300 microns fiberoptic fiber coupled with an argon laser (HGM, model 20) was inserted to the anterior chamber and positioned at the trabecular meshwork. A patent sclerostomy was created in all 9 eyes by 1 to 3 laser pulses with an energy of 4W with a duration of 0.5 second. Preoperative intraocular pressure in treated eyes and untreated eyes, measured with a pneumatic tonometer, was the same. After one month, the intraocular pressure of the treated eyes was 4.6 +/- 0.4mmHg lower than that of the untreated eyes. Histologic study revealed that the sclerostomies with a diameter of 200-300 microns from the anterior chamber opening to the subconjunctival space were patent at one month after the treatment. Internal sclerostomy with a high powered argon endolaser may hold potential as a new filtering procedure which can easily be performed with a minimum of conjunctival damage.