Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis

source extracted confidence: high 2026-04-09
#collagen #corneal-stroma #corneal-topography #cross-linking-reagents #humans

Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis

Borchert et al., 2022 | Asia Pac J Ophthalmol (Phila) | Meta Analysis

Citation

Borchert Grace A, Watson Stephanie L, Kandel Himal. Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis. Asia Pac J Ophthalmol (Phila). 2022-Sep-01;11(5):453-459. doi:10.1097/APO.0000000000000555

Abstract

PURPOSE: Keratoconus is a disorder that results in visual loss from increased corneal high-order aberrations and irregular astigmatism and reduces quality of life. The primary treatment for progressive keratoconus is crosslinking (CXL). Recently, it has been suggested that oxygen enhances the type II photodynamic reaction of CXL that is oxygen dependent. Our study investigated the effect of increased oxygen availability in epithelium-on CXL on visual acuity and corneal curvature. METHODS: We searched PubMed, EMBASE, Medline, Web of Science, and Scopus databases on November 3, 2021. We included studies that reported increased oxygen availability during CXL in patients with keratoconus published within the last 10 years. A meta-analysis on the primary outcomes, maximum keratometry, and corrected distance visual acuity, was conducted. RESULTS: The search yielded 108 publications which were screened and assessed for eligibility. Six studies were included in the systematic review and 5 studies were included in our meta-analysis of the outcomes of increased oxygen availability in accelerated CXL. The meta-analysis on data after 6 months of follow-up found a significant decrease in mean maximum keratometry of 1.2 diopter (95% confidence interval: 0.2-2.3; P =0.02) and an improvement in mean corrected distance visual acuity by 0.08 logMAR (95% confidence interval, 0.02-0.13; P =0.01). There were no serious adverse events reported. CONCLUSIONS: Increasing oxygen during epithelium-on CXL improved visual acuity and produced corneal flattening without any serious adverse events in patients with keratoconus. The demarcation line depth was significantly higher with oxygen compared to the control group. Further data are required with a control group and long-term follow-up across a range of CXL protocols for implementation into standard clinical practice.

Key Findings

The search yielded 108 publications which were screened and assessed for eligibility. Six studies were included in the systematic review and 5 studies were included in our meta-analysis of the outcomes of increased oxygen availability in accelerated CXL. The meta-analysis on data after 6 months of follow-up found a significant decrease in mean maximum keratometry of 1.2 diopter (95% confidence interval: 0.2-2.3; P =0.02) and an improvement in mean corrected distance visual acuity by 0.08 logMAR

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population keratoconus published within the
Sample Size 5
Age Range See abstract
Condition See abstract

MeSH Terms

  • Collagen
  • Corneal Stroma
  • Corneal Topography
  • Cross-Linking Reagents
  • Humans
  • Keratoconus
  • Oxygen
  • Photosensitizing Agents
  • Quality of Life
  • Riboflavin
  • Ultraviolet Rays

Evidence Classification

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

Provenance

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