Changes in IOP and HIstopathology Following Contact Transscleral Cyclophotocoagulation with Diode Laser in High Tension Rabbit Eyes

ABSTRACT

We evaluated the acute and long term intraocular pressure(IOP) lowering effect of diode laser contact transscleral cyclophotocoagulation by applying G probe to argon laser induced high tension pigmented rabbits through the changes in IOP and histopathology. Eighteen eyes of 18 high tension pigmented rabbits were treated with diode laser contact transscleral cyclophotocoagulation (24-30 application) 0.5mm posterior to the limbus over 360degrees and the other eyes were used as controls. The rabbits were divided into 3 groups according to the energy levels of diode laser (1st group; 0.8J of energy, 2nd; 1.0J of energy, and 3rd; 1.2J of energy). There were mean decrease in IOP of 24.4%, 38.4%, and 38.7% in 1st, 2nd, and 3rd groups respectively during 5 weeks after tratment (p<0.05). After treatment, microendoscopic findings of the ciliary body revealed blenching in 1.0 and 1.2J groups. Light microscopy 1 day after treatment revealed coagulation necrosis of the pigmented and nonpigmented ciliary epithelium, congestion of vessels, thrombosis, and pigment dispersion in all energy groups, with destruction increasing in relation to power. Five weeks after treatment, atrophy and fibrosis of the ciliary nonpigmented and pigmented epithelium and stroma were observed in all groups.