Endoscopic Cyclophotocoagulation and Other Cyclodestructive Modalities

Abstract Purpose To compare the histological effects of endoscopic cyclophotocoagulation (ECP) with other forms of ciliary body ablative procedures. A secondary aim was to correlate these findings with historical clinical success and complication rates. Design Prospective qualitative comparison of histopathological tissue analysis, Subjects/Participants/Controls Two eyes of two patients who had undergone ECP for open angle glaucoma were studied. Two eyes from a normal monkey were treated with ECP and studied. For comparison, one eye each of patients who had undergone contact and non-contact Nd:YAG transscleral cyclophotocoagulation (TCP) for open angle glaucoma were analyzed. Methods The human globes were enucleated and submitted for analysis by gross exam, light and electron microscopy. Monkey eyes were studied by gross exam and light microscopy after 1 week, 2 weeks and 1 month following ECP. Main Outcome Measures Gross and histopathology specimens of all subjects were analyzed with respect to location and type of tissue effects and degree of collateral damage. Results The gross analysis of all ECP specimens showed a uniform anterior to posterior whitening of each treated ciliary process. This correlated with microscopic evidence of loss of pigmentation from the pigmented ciliary epithelial cells seen with mostly preserved architecture and vasculature of the ciliary processes. By comparison, the TCP specimens showed erratic treatment of the ciliary processes with overlap into the pars plicata of the ciliary body. Microscopic analysis revealed significant disruption of the cells throughout the ciliary processes and loss of vessels within the stroma. Conclusions Treatment with ECP results in less overall tissue destruction and a targeted effect on the pigmented ciliary epithelium of the ciliary processes, when compared to TCP.