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

Summary

This meta-analysis of 10,558 cases identifies glaucoma, keratoconus, diabetes, older age, and elevated intraocular pressure as key predictors of poor outcomes in high-risk corneal transplantation, emphasizing individualized preoperative optimization and surgical planning to improve graft survival and visual prognosis.

Abstract

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.

Introduction

Corneal transplantation remains the definitive treatment for various corneal diseases, offering significant potential to restore vision and enhance quality of life^1,2. Although generally effective, the outcomes of this procedure are often suboptimal in high-risk patients, defined as individuals with conditions that predispose them to graft failure or postoperative complications³. High-risk corneal transplantation refers to procedures performed in patients with an increased risk of graft failure or postoperative complications, such as those with prior graft failures, glaucoma, or progres....

Protocol

Literature retrieval
A systematic search was conducted to identify studies evaluating factors influencing the efficacy of high-risk corneal transplantation. Relevant studies were retrieved from English-language databases, including PubMed, Cochrane, Embase, Google Scholar, and Web of Science. The search covered the period from the inception of each database through December 31, 2024. The search terms used included high-risk corneal transplantation, glaucoma, keratoconus, graft survival, postoperative visual acuity, and corneal transplant outcomes as detailed in Table 1. The search strategy was executed in accordance with the PRI....

Results

Baseline characteristics of patients
In this meta-analysis, the initial search identified 432 articles. After screening titles and abstracts, 23 articles were found to meet the inclusion criteria. Upon a detailed review of the full texts, 12 articles were excluded, including 4 due to unavailable data and 8 due to unrelated intervention methods. Ultimately, 11 eligible articles, encompassing a total of 10,558 cases of corneal transplantation, were included in the meta-analysis. These comprised 4,012 c.......

Discussion

Corneal transplantation is a critical procedure for restoring vision in patients suffering from various corneal diseases²⁹. Corneal transplantation provides an important opportunity to improve the quality of life of patients with advanced corneal diseases. In recent decades, advances in surgical techniques, including Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK), have substantially improved graft outcomes²⁰

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Cochrane Library	Cochrane Collaboration	N/A	Systematic review database
Embase	Elsevier	N/A	Biomedical literature retrieval
EndNote	Clarivate Analytics	v20	Reference management
Microsoft Excel 2021	Microsoft Corporation, Redmond, WA, USA	v2021	Data tabulation and visualization
Newcastle–Ottawa Scale (NOS)	Ottawa Hospital Research Institute	N/A	Study quality evaluation
PRISMA 2020	EQUATOR Network	DOI:10.1136/bmj.n71	Reporting guideline compliance
PubMed	National Library of Medicine (NLM)	N/A	Literature retrieval
STATA (v18.0)	StataCorp LLC, College Station, TX, USA	v18.0	Statistical analysis (meta-analysis, heterogeneity, funnel plots)
Web of Science	Clarivate Analytics	N/A	Citation and reference tracking