Transscleral Pars Plana Choroid Ablation Using the Iridex Laser System Yields Improvements for Surgical Insertion of the Port Delivery Implant in a Minipig Model.

Purpose: To evaluate an alternative surgical approach for Port Delivery System with ranibizumab (PDS) implant and a novel application of Iridex laser system in Gottingen minipig model.

Methods: A total of seventeen male minipigs (Part 1: 9 animals in non-recovery and Part 2: 8 animals observed for 8-days post-surgery Part 2) received PDS implant insertion into each eye. The effect of Iridex 810 nm infrared diode laser with varying energy (power or duration) on transscleral pars plana ablation, surrounding ocular tissue and postsurgical vitreous hemorrhage (VH) was investigated.

Results: The most effective laser parameters for transscleral pars plana ablation in mitigating vitreous hemorrhage with no surrounding tissue damage were continuous wave mode, 1750 mW, 1000 ms, and 16 spots (8 overlapping spots/sweep applied over 2 rows) across a 4 mm segment, posterior to the limbus, delivering a total energy of 28 J. Minimal self-limiting scleral hemorrhage was observed with two of the implants and no VH were observed. µCT imaging was consistent with clinical ophthalmic.

Observations: On microscopic observations, no tissue damage was observed at these laser settings.

Conclusion: This Göttingen minipig model demonstrated a novel application of Iridex laser for transscleral pars plana ablation that streamlines the PDS implantation surgery.