Postoperative Corneal Dellen Following PreserFlo MicroShunt: A Case Report

BACKGROUND The PreserFlo MicroShunt is a subconjunctival drainage device increasingly used to manage open-angle glaucoma. While its safety profile is considered favorable compared with that of trabeculectomy, rare postoperative complications, including corneal surface pathology, can still be encountered. To our knowledge, corneal dellen has not been previously reported following PreserFlo implantation. CASE REPORT A 15-year-old boy with pathological myopia and Stickler syndrome underwent PreserFlo MicroShunt implantation for refractory secondary open-angle glaucoma. Two weeks postoperatively, he developed a temporal area of corneal stromal thinning consistent with dellen, located adjacent to an elevated bleb in the horizontal plane. Conservative therapy, including a switch from prednisolone acetate to loteprednol etabonate, intensive preservative-free lubrication, autologous serum drops, and bandage contact lens placement, was initiated. Full corneal re-epithelialization and recovery were achieved within 1 week, without compromising bleb function or intraocular pressure control. CONCLUSIONS Corneal dellen is a potential, although previously undocumented, complication of PreserFlo MicroShunt surgery, particularly when bleb elevation is prominent in areas not protected by the eyelid. Prompt recognition and targeted conservative therapy may allow for complete recovery while preserving device function and visual outcomes. Surgeons should monitor the ocular surface for this complication and adjust postoperative management accordingly.