The Subject-Fixated Coaxially Sighted Corneal Light Reflex: A Clinical Marker for Centration of Refractive Treatments and Devices

Abstract

In their recent article, “The Subject-Fixated Coaxially Sighted Corneal Light Reflex: A Clinical Marker for Centration of Refractive Treatments and Devices,” Chang and Waring review definition, application, and usage of ocular reference axes and angles as well as inconsistencies among them. 1 Chang D.H. Waring IV, G.O. The subject-fixated coaxially sighted corneal light reflex: a clinical marker for centration of refractive treatments and devices. Am J Ophthalmol. 2014; 158: 863-874 Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar A literature review is presented comparing reference axes, points, and alternative names in relation to various intraocular and extraocular reference landmarks. The authors describe the variable and, in part, conflicting definitions used in the literature and their lack of clinical applicability. Many of these definitions are adapted from textbook geometrical optics definitions for axis and rotationally symmetrical optical systems. 2 Fry G.A. Geometrical Optics. Chilton, Philadelphia1969: 106-111 Google Scholar During my career as a vision scientist these inconsistencies have led to misunderstandings and misinterpretations and left me with doubt about the full understanding of the matter on several occasions in discussions with colleagues or while researching the relevant literature. The authors dismantle this complexity and lay bare the shortcomings in an exemplary way. The Subject-Fixated Coaxially Sighted Corneal Light Reflex: A Clinical Marker for Centration of Refractive Treatments and DevicesAmerican Journal of OphthalmologyVol. 158Issue 5PreviewTo describe the inconsistencies in definition, application, and usage of the ocular reference axes (optical axis, visual axis, line of sight, pupillary axis, and topographic axis) and angles (angle kappa, lambda, and alpha) and to propose a precise, reproducible, clinically defined reference marker and axis for centration of refractive treatments and devices. Full-Text PDF ReplyAmerican Journal of OphthalmologyVol. 159Issue 3PreviewWe would like to thank Dr Buehren for affirming the need and utility of the concepts that we introduce in our paper.1 It is encouraging to have independent acceptance and validation of our proposed approach for the purposes of assessing and discussing the topic of centration. We hope that these concepts continue to gain broad adoption in the field. When all discussion about centration is done with the same consistent terminology, progress in the field will be accelerated. Full-Text PDF