Redefining Keratoconus: A Novel Functional Classification System for Enhanced Diagnosis and Treatment

Keratoconus has been the subject of numerous classification systems over time, yet a universally accepted framework remains elusive, reflecting the disease's complexity and multifactorial nature. 1 The first classification of keratoconus based on disease progression was introduced by Amsler.This was later refined by Krumeich et al., who expanded upon Amsler's work to develop the widely recognized Amsler-Krumeich grading system for keratoconus. 2Since then, numerous classification systems have been introduced, including higher order aberrations by Aio-Shabayek, 3 irregularity indices by Ishi, 4 the morphological classification of keratoconus for intracorneal ring implantation (ICR) by Alfonso et al. 5 and the innovative Belin ABCD keratoconus staging system, which evaluates anterior and posterior corneal curvature centered on the thinnest point, thinnest pachymetry values, and distance visual acuity, grading the condition from 0 to 4. 6 This short paper proposes a novel functional classification of keratoconus into three grades according to the symptoms (shadows, glare, starbursts), uncorrected (UDVA), best-corrected (CDVA), and potential distance visual acuity (PVA) measured by the best-fit contact lens: 7