Corneal topographic analysis in patients with keratoconus using 3-dimensional anterior segment optical coherence tomography.

PURPOSE: To assess a new corneal topographer based on 3-dimensional anterior segment optical coherence tomography (OCT-based corneal topographer) for analyzing corneal topography in patients with keratoconus.

SETTING

Osaka University Graduate School of Medicine, Osaka, Japan.

DESIGN

Evaluation of diagnostic test or technology.

METHODS

Keratoconic eyes and normal control eyes were assessed using a rotating Scheimpflug-based corneal topographer and an AS OCT-based corneal topographer. The OCT-based corneal topographer, a 1310 nm swept-source device, captures 8192 points during 0.34 second for 16 radial scans of the corneal topography. The success rate of precisely digitizing the corneal surfaces, patterns of the color-coded maps, central corneal thickness (CCT), and central axial power were compared between the 2 devices.

RESULTS

Forty keratoconic eyes and 30 control eyes were assessed. The OCT-based corneal topographer measured corneal configurations despite corneal opacities. The success rate of precisely digitizing the corneal surfaces in keratoconic eyes was 95% using OCT and 80% using the Scheimpflug-based corneal topographer. The color-coded maps of the anterior and posterior corneal elevations, CCT, and corneal axial power maps generated by the 2 devices agreed well. The correlations between the CCT values and between the central corneal axial power values measured by the 2 devices were well correlated in both groups.

CONCLUSIONS

The OCT-based corneal topographer, with its faster acquisition time, provided more consistent measurements than the Scheimpflug-based corneal topographer. The OCT-based corneal topographer seems promising for evaluating highly irregular corneas, as in cases of advanced keratoconus.

FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.