Allergic Rhinitis and Keratoconus: A Systematic Review and Meta-Analysis

Background: The relationship between keratoconus and various allergic diseases has been a subject of controversy.

Objective: In the present study, a systematic review and meta-analysis was conducted to investigate the association between allergic rhinitis (AR) and keratoconus.

Methods: Relevant and eligible studies from PubMed, Web of Science, and the Cochrane Library were systematically reviewed to evaluate the association between AR and keratoconus. Observational studies that reported the number of patients with and without keratoconus, as well as the number of patients with keratoconus diagnosed with or without AR, were included. Two reviewers independently screened eligible studies and extracted data. A bivariate meta-analysis was conducted to calculate the pooled odds ratio of keratoconus in patients with versus without AR. A sensitivity analysis was performed using the adjusted odds ratio reported in the included studies to validate the findings.

Results: Seven studies involving 775,574 participants were included in the meta-analysis. Among them, 29,082 patients had keratoconus. The pooled odds ratio of keratoconus in patients with AR was 1.71 (95% confidence interval [CI]: 1.36-2.15; P < .001; I² = 96%), and the pooled adjusted odds ratio was 1.72 (95% CI: 1.23-2.40; P = .001; I² = 97%).

Conclusions: Patients with AR have significantly higher odds of keratoconus than those without AR. Future studies are warranted to investigate the causal relationship and evaluate the cost-effectiveness of early screening, using methods such as corneal topography, and referral for keratoconus in patients with AR.