Central and peripheral corneal thinning in keratoconus

Abstract

Purpose: Recent data regarding the mid-peripheral portion of the removed corneal button in transplant surgery indicate histopathologically that keratoconus was present also in the peripheral portion of the button. The intent of this study was therefore to investigate if peripheral changes could also be detected clinically by measuring the central and peripheral corneal thickness of KC patients.

Methods: Corneal pachymetry was measured with the Visante optical coherence tomography and Orbscan II. Of 52 subjects, 26 were KC subjects and 26 were age- and sex-matched control subjects.

Results: Corneal thickness, in KC patients, was significantly reduced in all areas compared with corneal thickness among controls with both the Visante optical coherence tomography and Orbscan II.

Conclusion: The results of the present study have provided clinical evidence that KC is a disease affecting a wider area of the cornea. Although the KC cornea shows the greatest change in thickness in the ectatic region, this attenuation declines toward the periphery. The presence of peripheral thinning indicated that KC may be a "pancorneal" pathology and not limited to the ectatic portion.