I read with great interest the article by Dr Maeda and associates1 on the comparison of methods for detecting keratoconus using videokeratography. While those of us who routinely use topography for the evaluation of keratoconus in patients realize the power of this technology in clinical practice, there are great difficulties involving both philosophy and statistics in trying to quantitate its effectiveness in detecting early disease, as this study attempts to do.
As a technology improves to the point of making a diagnosis prior to the development of clinical disease, the disease itself can no longer be as previously defined. What is keratoconus? Dr Maeda et al use Krachmer's definition, "a noninflammatory corneal thinning disorder that produces irregular astigmatism due to distortion of the cornea."2 Can we, then, make a diagnosis of "early keratoconus" in the absence of those characteristics? Perhaps all we can say with any real truthfulness
Goren MB. Comparison of Methods for Detecting Keratoconus Using Videokeratography. Arch Ophthalmol. 1996;114(5):631. doi:10.1001/archopht.1996.01100130623029