Abstract

Abstract

: Before the appearance of recent tomographic imaging and membrane cross-linking (CXL), identification and treatment of ectatic unwellness was restricted to disease severity during which changes to the anterior corneal surface resulted in visual disturbances. Rigid contact lenses and/or penetrating corneal transplant treated advanced disease, as a result of early or subclinical identification of disease wasn't doable or its necessity was appreciated. The emergence of cardinal as a viable treatment to switch the natural progression of astigmatism has enlarged the requirement for higher diagnostics. Many strategies are delineated within the literature to assess and document the progression of keratoconus, however there's no consistent definition of the progression of ectasia. the foremost recent imaging techniques (eg tomography) have created it doable to notice ectatic unwellness early, before loss of vision and subjective disorders.Belin' ABCD classification/staging system was introduced on a Scheimpflug imaging system [Pentacam, (Oculus GmbH, Wetzlar, Germany)] to handle previous shortcomings. The ABCD system uses four parameters: anterior ("A") and posterior ("B" for the back) radius of curvature taken in an exceedingly three.0 metric linear unit optical zone targeted on the thinnest point, "C" is that the minimum membrane thickness and “D” vision of the most effective show distance. The primary 3 parameters (A, B, C) are mechanically generated objective measures that may be accustomed to confirm progressive change.The staging system isn't restricted to a selected industrial entity and might be incorporated in any tomographic imaging system. The ABCD Pro- gression show diagrammatically displays every parameter and shows once applied mathematics amendment on top of measuring noise is reached. this {could} permit the practician the power to diagnose progressive unwellness at a far earlier stage than was antecedently possible, with the arrogance that earlier intervention could stop visual loss.