We would like to thank Dr Buehren for affirming the need and utility of the concepts that we introduce in our paper. 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.
We further agree that our proposed descriptive nomenclature is precise yet verbose. Dr Buehren’s proposed eponymous terminology would certainly make these concepts easier to reference. What may be lost with such nomenclature is the clear and unambiguous descriptive nature of the originally proposed terminology. Nevertheless, if careful attention is paid to coaxiality and fixation when applying these principles and definitions, then we support the use of the terms Chang-Waring reflex, Chang-Waring axis, and Chang-Waring chord.
Furthermore, while the description of Chang-Waring chord (chord mu) is correct in the text of our article, the labels in Figure 5 are incorrect. Reference to the Chang-Waring chord, as defined as the displacement from the Chang-Waring reflex to the pupil center, should read 0.25 mm @ 117 degrees in the photopic (Top) figure and 0.36 mm @ 203 degrees in the scotopic (Bottom) figure of this right eye.
Additionally, since right and left eyes demonstrate reflectional symmetry, an analysis of the relative position between markers in an eye should make reference to which eye is being analyzed. A description of the Chang-Waring chord should therefore be expressed in 1 of 3 notations to account for sidedness: (1) a radial coordinate system with a right or left eye designation; (2) a cartesian coordinate system with reference to nasal being positive and temporal being negative; or (3) a cartesian coordinate system with reference to the viewer’s right being positive and the viewer’s left being negative. Finally, owing to the chirality in orientation of intraocular lenses with C-loop haptics in the eye, studies of IOL centration should consider separate analyses of right and left eyes.