Inter-expert agreement on epithelial thickness mapping for refractive surgery screening: variability highlights need...

Area of Science:

• Ophthalmology
• Corneal Imaging
• Refractive Surgery

Background:

• Accurate assessment of corneal tomography is crucial for keratorefractive surgery candidacy.
• Epithelial thickness mapping provides additional data for evaluating corneal health and ectasia risk.

Purpose of the Study:

• To assess inter-expert agreement on interpreting epithelial thickness maps.
• To determine how epithelial mapping influences surgical eligibility decisions for keratorefractive surgery candidates.

Main Methods:

• A retrospective review of 103 corneal tomography cases (normal, borderline, keratoconic) by four experts.
• Experts initially assessed eligibility using Scheimpflug tomography, then re-evaluated with added anterior segment OCT-based epithelial thickness maps.
• Inter-rater agreement was measured using Fleiss' kappa, and imaging modality influence was ranked.

Main Results:

• Epithelial mapping altered eligibility in 19% of cases, predominantly increasing eligibility for borderline cases.
• Inter-rater agreement on eligibility was moderate (κ=0.43) after adding epithelial maps but remained poor for borderline cases (κ=0.12).
• Corneal topography and Belin-Ambrosio-Display (BAD) were deemed most influential, followed by epithelial mapping.

Conclusions:

• Epithelial mapping can shift keratorefractive surgery eligibility decisions, particularly towards increased eligibility.
• Poor inter-expert agreement on epithelial map interpretation underscores the need for standardized protocols.
• Standardized, safety-oriented interpretation of epithelial maps is essential for consistent ectasia risk assessment before refractive surgery.