When keratometric measurements do not accurately reflect corneal topography.

The keratometer has been the standard for measuring corneal curvature for decades and until recently seemed sufficient for most clinical situations. However, it measures only four points from a small region of the cornea and assumes that the cornea is symmetrical. We document with a number of examples a variety of clinical cases in which keratometry provides either incomplete or frankly misleading information. We believe that corneal topography is now an invaluable clinical tool and will replace the keratometer in standard clinical practice.