Association between corneal densitometry at initial presentation and future progression across age groups in...

This study investigated corneal densitometry values at presentation, acquired via Scheimpflug imaging, in eyes with and without documented progression. The aim was to determine whether corneal densitometry values at presentation were associated with the likelihood of future progression.

Initial Scheimpflug images from keratoconic eyes with a minimum 1-year follow-up and ≥3 visits were analysed. Progression was defined based on the Belin ABC 'red gate' criteria. Corneal densitometry was quantified in the anterior one-third and posterior two-thirds within the central 1 mm zone and concentric annular zones (1-2, 2-4 and 4-6 mm), assessed along the vertical, horizontal and oblique meridians. Normalised densitometry values were compared between progressive and non-progressive eyes across four age groups using linear mixed-effects models.

A total of 491 eyes were analysed, with progression rates of 66.7% (≤18 years, 39 eyes), 48.7% (>18 to ≤24 years, 187 eyes), 45.6% (>24 to <30 years, 149 eyes) and 34.5% (≥30 years, 116 eyes). In the ≤18-year-old group, progressive eyes showed significantly higher anterior one-third densitometry values at the 1 mm central zone (p = 0.02), 1-2 mm (p = 0.02) and 2-4 mm (p = 0.02) annular zones. In the ≥30 year age group, progressive eyes had lower anterior and posterior densitometry values at the 1 mm central zone (p = 0.02, p = 0.01), 1-2 mm (p = 0.03, p = 0.02) and 2-4 mm (p = 0.04, p = 0.01) annular zones. No differences were observed in the other groups.

These findings suggest that greater densitometry values in the anterior one-third of the cornea are linked with a higher risk of future progression in younger keratoconic patients. The higher densitometry values and association with future progression may indicate heightened disease activity driven by microstructural changes, ocular surface inflammation and increased keratocyte activity. In contrast, higher densitometry values from age-related corneal cross-linking may explain the non-progressive course in older patients.