Oxidative and antioxidative stress markers in keratoconus: a systematic review and meta-analysis

source extracted confidence: high 2026-04-09
#antioxidants #aqueous-humor #biomarkers #cornea #humans

Oxidative and antioxidative stress markers in keratoconus: a systematic review and meta-analysis

Navel et al., 2021 | Acta Ophthalmol | Meta Analysis

Citation

Navel Valentin, Malecaze Jean, ... Dutheil Frédéric. Oxidative and antioxidative stress markers in keratoconus: a systematic review and meta-analysis. Acta Ophthalmol. 2021-Sep;99(6):e777-e794. doi:10.1111/aos.14714

Abstract

PURPOSE: To conduct a systematic review and meta-analysis on the levels of oxidative stress markers and antioxidants in keratoconus compared to healthy subject. METHOD: The PubMed, Cochrane Library, Embase, Science Direct and Google Scholar databases were searched on 1st June 2020 for studies reporting oxidative and antioxidative stress markers in keratoconus and healthy controls. Main meta-analysis was stratified by type of biomarkers, type of samples (tears, cornea, aqueous humour and blood) and type of corneal samples (stromal cells, epithelium and endothelium). RESULTS: We included 36 articles, for a total of 1328 keratoconus patients and 1208 healthy controls. There is an overall increase in oxidative stress markers in keratoconus compared with healthy controls (standard mean deviation (SMD) = 0.94, 95% confidence interval (95% CI) 0.55-1.33), with a significant increase in reactive oxygen and nitrogen species (1.09, 0.41-1.78) and malondialdehyde (1.78, 0.83-2.73). There is an overall decrease in antioxidants in keratoconus compared with healthy controls (-0.63, -0.89 to -0.36), with a significant decrease in total antioxidant capacity/status (-1.65, -2.88 to -0.43), aldehyde/NADPH dehydrogenase (-0.77, -1.38 to -0.17), lactoferrin/transferrin/albumin (-1.92, -2.96 to -0.89) and selenium/zinc (-1.42, -2.23 to -0.61). Oxidative stress markers were higher in tears and in cornea of keratoconus than in aqueous humour, and antioxidants were decreased in tears, aqueous humour and blood without difference between sample type. Oxidative stress markers increased in stromal cells and antioxidants decreased in endothelium. CONCLUSION: Oxidative stress markers and antioxidants were dysregulated in keratoconus, involving an imbalance of redox homeostasis in tears, cornea, aqueous humour and blood.

Key Findings

We included 36 articles, for a total of 1328 keratoconus patients and 1208 healthy controls. There is an overall increase in oxidative stress markers in keratoconus compared with healthy controls (standard mean deviation (SMD) = 0.94, 95% confidence interval (95% CI) 0.55-1.33), with a significant increase in reactive oxygen and nitrogen species (1.09, 0.41-1.78) and malondialdehyde (1.78, 0.83-2.73). There is an overall decrease in antioxidants in keratoconus compared with healthy controls (-0.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size 36
Age Range See abstract
Condition stress

MeSH Terms

  • Antioxidants
  • Aqueous Humor
  • Biomarkers
  • Cornea
  • Humans
  • Keratoconus
  • Oxidative Stress
  • Tears

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: zinc

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09