Redefining forme fruste keratoconus as ectasia susceptibillity

Abstract

The term form fruste keratoconus was initially coined by Marc Amsler in 1938 in cases with slightly tilted Java mires and, later on, longitudinal studies using Polaroid Placido photokerastocopy for describing patterns of irregularity that did precede clinical keratoconus. The term fruste is derived from French and means "confused, crude, or unfinished." Fruste refers to an incomplete and abortive form of the disease, in contrast to the concept of the full-blown presentation. Rabinowitz describes forme fruste keratoconus as the eyes with unremarkable biomicroscopy and no visual impairment having good distance corrected visual acuity by glasses, which present a typical keratoconus irregularity on the topographic mapping. In 2009, Klyce proposed that the term forme fruste keratoconus should also apply to the contralateral eye of keratoconus patients with no clinical findings of any sort. There is no consensus on the current definition of forme fruste keratoconus. The recent 2015 Global consensus states that keratoconus is bilateral disease and that ectasia may occur unilaterally due to purely biomechanical stress. Nevertheless, FFCK has been recognized as the most important risk factor for developing progressive ectasia after refractive laser correction. This article provides a prospective review of the definition of forme fruste keratoconus as the cases with high susceptibility for corneal biomechanical decompensation and ectasia progression.