Evolution Profiles of Different Corneal Parameters in Progressive Keratoconus
To analyze the evolution profiles of several corneal topographic and tomographic parameters in progressive keratoconus and compare to the kinetic of evolution of the gold standard parameter, the anterior keratometry.
One hundred and twenty four eyes of 62 patients with mild to severe keratoconus were prospectively enrolled and followed every 3 months during at least 1 year. Fifty-six corneal parameters were measured at each visit using a combined Placido-based and dual Scheimpflug imaging system. Means and percentage of progression (PP) between each visit were calculated for each parameter and compared to the anterior keratometry changes using the Student's t-test.
At 1 year, 12% (15/124) of eyes progressed with an increase in anterior keratometry of 1D or more. Among these eyes, posterior steepest keratometry and vertical coma had a significantly higher percentage of progression (p < 0.01) than the anterior keratometry and occurred significantly earlier (p < 0.01) than the modifications of the anterior keratometry, with changes noted on average at 6.2, 5.9 and 10.1 months, respectively for posterior keratometry, vertical coma and anterior keratometry. Pachymetric-related parameters did not show significant changes between the progressive and non-progressive eyes.
Modifications of the posterior keratometry and vertical coma occurred significantly earlier than the anterior keratometry in progressive keratoconus eyes. These parameters may be relevant warning signs when monitoring progressive keratoconus.