Iatrogenic Keratoconus Secondary to Long-term Excessive Bleb Massage Following Bilateral Glaucoma Drainage Device Implantation: A Case Report

Abstract Background: Keratoconus (KC) is a bilateral corneal ectatic disorder characterized by progressive corneal thinning and protrusion, with chronic eye rubbing being its most important non-genetic risk factor. Iatrogenic KC caused by bleb massage is rare. We report a case of bilateral iatrogenic KC in a patient with bilateral primary open-angle glaucoma (POAG) following bilateral Ex-PRESS glaucoma drainage device implantation, secondary to long-term excessive bleb massage (more than 5 times per day for approximately 7 years), in order to raise clinicians' awareness of this rare complication. Case presentation: A 41-year-old woman with bilateral POAG underwent bilateral Ex-PRESS glaucoma drainage device implantation at our hospital in 2017. Postoperative intraocular pressure (IOP) was approximately 10 mmHg, and regular bleb massage was advised. After 2019, the patient did not return for scheduled follow-up visits and performed self-administered massage approximately 5 times daily with considerable force. In January 2024, astigmatism of -10.00 DC developed in the left eye. In November 2024, visual acuity declined markedly in both eyes (0.1 in the right eye and 0.02 in the left eye). Corneal topography and anterior segment OCT revealed typical KC changes in both eyes, with a Kmax of 71.3 D in the left eye, accompanied by corneal scarring and central epithelial erosion. The patient was diagnosed with bilateral iatrogenic KC. After massage was discontinued, IOP remained stable at 10 mmHg. The patient is currently awaiting corneal transplantation, with the left eye prioritized. Conclusions: Non-standard or excessive bleb massage may induce iatrogenic KC through long-term repetitive mechanical stress and transient IOP elevation. Standardized postoperative patient education, regular corneal topography monitoring, and vigilance for unexplained progressive myopia or worsening astigmatism are essential to prevent this serious complication.