"Intrableb pigmentation following XEN implantation: A case series"

Purpose: To evaluate the incidence and to describe the characteristics of the intrableb pigmentation (IBP) following XEN63 implantation.

Methods: Retrospective case series of three eyes presenting a pigment dispersion in the filtering bleb after a XEN63 implantation for uncontrolled IOP. Demographic, clinical and imaging data were obtained from medical records.

Results: Three out of 40 patients who underwent XEN implantation (average age 70.67 years) showed an IBP during the 12 months postoperative period. The mean time of IBP onset was 50 days (range, 15-90). The slit lamp examination showed two IBP patterns: a "diffuse" pattern (2 patients) with multiple spots of pigmentation inside the bleb; a "punctiform" pattern (1 patient), with a single spot at the distal end of the device. The AS-OCT imaging confirmed the presence of IBP appearing as a hyperreflective spot/s in the context of the filtering bleb. The patient with the punctiform IBP experienced a distal XEN ostium obstruction with a decrease in bleb function. In one case the diffuse IBP occurred after a successful needling procedure. All the patients' IOP reported at the end of the follow-up was below 21 mmHg.

Conclusion: The development of IBP might occur after XEN implantation in various times and with different patterns. The IBP pattern can provide meaningful clues on the bleb filtering function. A proper follow-up based on slit lamp biomicroscopy, IOP measurement, and AS-OCT imaging is recommended to manage potential complications related to IBP.