Incidence and Progression of Glaucoma Following Boston Type 1 Keratoprosthesis: A Systematic Review and Meta-Analysis

Boston Type 1 Keratoprosthesis (KPro) implantation is an established surgery for severe corneal blindness when traditional keratoplasty is not feasible. This systematic review and meta-analysis aimed to quantify the incidence and progression of glaucoma following KPro implantation.

Despite advances in device design and postoperative management, glaucoma remains a sight-threatening complication. Accurate estimates of glaucoma incidence and progression can inform treatment decisions and enhance long-term visual outcomes in this high-risk population.

MEDLINE, Embase, and CENTRAL were systematically searched from inception to June 2025. Two independent reviewers performed title/abstract screening, full-text screening, data extraction, and risk-of-bias assessment, with discrepancies resolved through discussion with a third reviewer. Studies reporting glaucoma-related outcomes following KPro implantation were included. Random-effects meta-analyses were performed to estimate pooled incidences of postoperative glaucoma. Risk of bias was assessed using Joanna Briggs Institute tools, and certainty of evidence was evaluated using GRADE. This review was prospectively registered on PROSPERO (ID: CRD420251036643).

Twenty-three studies met inclusion criteria, encompassing 1,482 eyes with a mean follow-up of 39.4 months (±14.4). The mean patient age was 54.5 years (±8.9). Pre-existing glaucoma affected 45.9% of eyes. Overall, the pooled incidence of any form of postoperative glaucoma events was 25.6% (95% CI: 18.1-34.8%, I² = 87.3%) and an incidence rate of 0.09 events per eye-year (95% CI: 0.07-0.13; I² = 91.6%). Among studies explicitly reporting de novo glaucoma, the pooled incidence was 31.1% (95% CI: 20.6-43.9%, I² = 70.6%), while progression of pre-existing glaucoma occurred in 37.7% of eyes (95% CI: 17.9-62.6%, I² = 85.7%). Ocular hypertension without diagnostic confirmation of glaucoma was observed in 17.1% of eyes (95% CI: 5.6-41.9%, I² = 71.3%). Significant heterogeneity was observed across studies, stemming from variability in outcome definitions, indication for KPro, and reporting practices.

Glaucoma represents a clinically important complication following KPro implantation, affecting approximately one-quarter to one-third of eyes postoperatively. Although the certainty of evidence is very low due to heterogeneity and variability in diagnostic definitions, the results underscore the need for vigilant perioperative monitoring and standardized diagnostic approaches.