Improvement of the loss of corneal endothelial cells by relocating the tip of the Baerveldt® implant tube from the anterior chamber to the vitreous cavity

Purpose: It has been reported that corneal endothelial cells (CEC) decrease faster when the tip of the Baerveldt glaucoma implant (BGI) tube is inserted into the anterior chamber than into the vitreous cavity. We investigated whether surgically relocating the tip of the BGI tube from the anterior chamber to the vitreous cavity could reduce CEC loss. Patients and methods: This was a single facility retrospective cohort study. The inclusion criteria were the CEC density less than 1500 cells/mm² and the CEC reduction ratio was greater than 10%/year. The subjects were 11 consecutive patients that could be followed > 12 months after relocation surgery. All patients were undergone vitrectomy, and the tip of tube was inserted into the vitreous cavity from the anterior chamber. We compared the intraocular pressure (IOP), reduction slope of CEC density and annual reduction rate of CEC density before and after relocation surgery. We calculated the annual reduction ratio in comparison with the preoperative CEC density (%/year). Results: The mean of period between the Baeveldt with anterior chamber insertion surgery and the relocation surgery was 33.8 ± 15.0 months. The mean of follow-up after relocation surgery was 21.8 ± 9.8 months. The relocation surgery did not significantly change IOP (p = 0.974). The mean preoperative and postoperative IOP were 13.1 ± 4.5 and 13.6 ± 4.3 mmHg. The reduction ratio of the CEC density was 15.4 ± 6.7 (%/year) before relocation surgery and significantly slower at 8.3 ± 6.5 (%/year) after relocation surgery (p = 0.024). Two patients resulted in bullous keratopathy after relocation surgery. Conclusions: Relocating the tip of BGI tube from the anterior chamber to the vitreous cavity could reduce CEC loss.