Asymmetrical Astigmatism with Inferior Steepening in Low Myopia as a Sign of Form Frust Keratoconus and Predicting Post-LASIK Ectasia

Objective: Retrospective study analysing the topographic maps of three cases with low myopia less than -6D developed post-LASIK ectasia and review of the criteria of predicting and diagnosing post-LASIK ectasia. Material and Methods: Analysis of the topgraphies and the history of developing of the ectasia which appeared nearly 2 years post-LASIK with no enhacment surgery or othe procedures. The presintation in two cases with keratites which was treated effectively by steriods. Results: The presince of asymetrical astigmatism with marked to moderate inferior steepening was the only sign predicting keratoconus suspect or post-LASIK ectasia. The detection of a difference between the K readings and the refracted astigmatism in 3 eyes where all show double the difference. Conclusion: The subjective nature of examiner interpretation of corneal topography remains highly variable,especially when diagnosing early keratoconus, and controversy exists regarding the minimum topographic criteria for diagnosing the earliest stages of subclinical keratoconus. This study further emphasizes the need for objective quantification of corneal topographic analysis of videokeratography.