Optometry

Visual acuity

Mathematics

Ectasia

Ophthalmology

Surgery

Curvature

Cornea

Geometry

Corneal topography

Keratoconus

Medicine

Indian Journal of Ophthalmology

Recent advances in the diagnosis and treatment of ectatic corneal disease have mandated a more modern staging system. The new Belin ABCD keratoconus staging system incorporates anterior and posterior curvature centered on the thinnest point of the cornea, thinnest pachymetry values and distance visual acuity in grades from 0-4. By including posterior curvature and thickness measurements based on the thinnest point, as opposed to apical, the new staging system better reflects anatomical changes seen in keratoconus and other ectatic diseases.

ABCD: A new classification for keratoconus