Mild topographic abnormalities that become more suspicious on Scheimpflug imaging.

PURPOSE: Although several screening methods exist, postoperative corneal ectasia after refractive surgery is a severe complication. One possibility for this might be the fact that screening methods may fail in detection of preoperative risk factors such as forme fruste keratoconus (FFKC).

METHODS: Retrospective evaluation of four cases that showed only mild changes of FFKC on placido-based topography but revealed indicative findings on Scheimpflug imaging (Pentacam).

RESULTS: While in placido-based topography evaluation of corneal topography did not show a clear FFKC, the evaluation of corneal topography on Scheimpflug imaging together with the data of spatial corneal thickness revealed distinctive FFKC in all cases presented.

CONCLUSIONS: Although both methods bear the risk of not detecting pre-existing FFKC, Scheimpflug imaging seems superior to placido-based corneal topography alone.