Corneal Epithelial Thickness Mapping: A Major Review

Area of Science:

• Ophthalmology
• Corneal Imaging
• Biomedical Engineering

Background:

• The corneal epithelium (CE) is vital for corneal integrity, exhibiting plasticity and compensatory mechanisms.
• Quantitative imaging, specifically epithelial thickness mapping (ETM), has advanced the characterization of CE remodeling patterns.

Purpose of the Study:

• To comprehensively review and synthesize available data on epithelial thickness mapping (ETM).
• To compare different ETM technologies and discuss their applications in normal and pathological corneas, as well as surgical contexts.

Main Methods:

• Systematic review of studies utilizing very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) for ETM.
• Exclusion of studies with manual corneal epithelial thickness (CET) measurements.
• Analysis of normative data and ETM in various corneal diseases and surgical scenarios.

Main Results:

• ETM provides detailed insights into CE remodeling in normal eyes, systemic diseases, and post-surgical states.
• Normative CET data and influencing factors (gender, age, diurnal variation, IOP) are discussed.
• ETM alterations are reviewed in conditions like keratoconus, dystrophies, infections, and post-refractive surgery.

Conclusions:

• ETM is a valuable tool for understanding corneal physiology and pathology.
• ETM has significant potential in guiding refractive surgery planning and assessing outcomes.
• ETM alterations are relevant in various ocular surface diseases and systemic conditions affecting the eye.