Comprehensive Corneal Thickness Evaluation: A Narrative Review of Past, Present and Future

Corneal thickness plays a fundamental role in assessing corneal health and diagnosing ectatic diseases. Initially, pachymetry relied on single-point measurements, particularly central corneal thickness (CCT). With the introduction of corneal tomography, it became possible to map corneal thickness at multiple locations, allowing for a more precise three-dimensional evaluation. In recent years, indices derived from spatial pachymetric profiles—such as the Corneal Thickness Spatial Profile (CTSP), Percentage Thickness Increase (PTI), and Ambrósio’s Relational Thickness (ART)—have significantly improved the sensitivity and specificity of early ectasia detection. Moreover, epithelial thickness analysis has gained relevance by enabling the identification of compensatory remodeling in early stages of disease. These advanced tools have also been applied in the post-refractive surgery setting, where distinguishing between naturally thin corneas and true ectatic thinning is crucial. This review aims to provide a comprehensive overview of corneal thickness evaluation over time, describe current methodologies, and discuss their clinical application in the early diagnosis and monitoring of corneal disorders.