Systematic Meta-Analysis of Impact of Glaucoma, Keratoconus, and Clinical Factors on High-Risk Corneal Transplantation Outcomes

High-risk corneal transplantation in patients with glaucoma, keratoconus, or prior graft failures is frequently associated with suboptimal outcomes. Although individual determinants such as age, gender, diabetes, and intraocular pressure (IOP) are recognized risk factors, their collective impact on graft survival has not been systematically quantified. This meta-analysis aims to clarify the role of glaucoma, keratoconus, and key clinical factors in shaping the prognosis of high-risk corneal transplantation. A systematic search of PubMed, Cochrane, Embase, and Web of Science databases was conducted to identify studies on high-risk corneal transplantation involving glaucoma and keratoconus. Data from 11 observational studies (10,558 cases) were analyzed. Across the included studies, transplant success was generally defined as graft survival with preserved corneal clarity. Subgroup analyses were performed to evaluate the impact of demographic and clinical determinants on transplant success. Glaucoma was found to significantly impact transplant success, with an odds ratio (OR) of 1.43 (95% CI [1.26, 1.63], p < 0.001), while keratoconus also represented a risk factor (OR = 1.22, 95% CI [1.13, 1.31], p < 0.001). Subgroup analysis for glaucoma patients indicated that younger age (<60 years), female gender, absence of diabetes, and preoperative IOP ≤25 mmHg were favorable factors for transplant success. In keratoconus patients, those under 30 years old and female had better transplant outcomes. Sensitivity analysis confirmed the robustness of these results, and minimal publication bias was observed. This study demonstrates that advanced age, male gender, diabetes, and elevated preoperative IOP significantly compromise the success of high-risk corneal transplantation. These findings provide robust evidence to guide patient selection, preoperative optimization, and surgical decision-making in high-risk populations. Incorporating these determinants into clinical practice may enhance graft survival and visual outcomes, while informing the development of tailored management strategies and future clinical guidelines.