Evaluation of the "G-Plant" glaucoma drainage device in rabbit eyes

Purpose: To evaluate the safety and efficacy of a new glaucoma drainage device, the "G-Plant", (Optanol, Israel) which is intended for primary filtering surgery. Materials and Methods: The "G-Plant" was implanted in 21 eyes of 11 rabbits through a 1 to 2 mm conjunctival opening located approximately 10 mm from the superior limbus under general anesthesia. No antimetabolites were used. The animals were then followed and the position of the drainage device, existence of filtering bleb, intraocular pressure (measured with pneumatonometer), depth of the anterior chamber and movement of the iris towards the internal opening of the device were monitored and recorded. Results: The results are listed in the following table: day 1 week 1 week 2 week 3-4 existing bleb 80% 80% 30% 0% IOP 13.9±2.8 17.4±3.1 18.9±2.8 20.7±2.6 shallow AC 10% 0% 0% 0% iris plugging 20% 30% 40% 55% Three out of the 21 devices had protruded out of the anterior chamber to the subconjunctival space. Conclusions: The "G-Plant" was found to be at least as safe and efficacious as conventional filtering procedure in rabbit eyes. Improvements are still needed to prevent protrusion and iris plugging of the internal opening.