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. 2021 Dec 13;9(12):e27363. doi: 10.2196/27363

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©Howard Maile, Ji-Peng Olivia Li, Daniel Gore, Marcello Leucci, Padraig Mulholland, Scott Hau, Anita Szabo, Ismail Moghul, Konstantinos Balaskas, Kaoru Fujinami, Pirro Hysi, Alice Davidson, Petra Liskova, Alison Hardcastle, Stephen Tuft, Nikolas Pontikos. Originally published in JMIR Medical Informatics (https://medinform.jmir.org), 13.12.2021.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Medical Informatics, is properly cited. The complete bibliographic information, a link to the original publication on https://medinform.jmir.org/, as well as this copyright and license information must be included.

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Schematic diagram illustrating the 4 basic corneal parameters that can be measured using corneal imaging. (A) pachymetry. (B) displacement: distance between the apex of the cornea and the point of minimum thickness. (C) and (D) represent 2 methods of calculating the best-fit sphere (BFS). In (C) the BFS is fitted to both the normal peripheral posterior surface (blue) and the abnormal anterior protrusion of the central posterior surface (green). In (D) the BFS is fitted to only the normal peripheral posterior surface (blue) excluding the abnormal central posterior surface (green), leading to a larger relative elevation than in (C). (E) the smallest radius of curve of the astigmatic corneal surface corresponds to the largest refractive power (Kmax) and the largest radius of curve corresponds to the smallest refractive power (Kmin). CCT: central corneal thickness.