Determination of optic axes by corneal topography among Italian, Brazilian and Chinese populations

Lopes, Bernardo, Eliasy, Ashkan ORCID: 0000-0002-4473-1900, Elhalwagy, Mohamed, Vinciguerra, Riccardo, Bao, Fangjun, Vinciguerra, Paolo, Ambrosio, Renato, Elsheikh, Ahmed ORCID: 0000-0001-7456-1749 and Abass, Ahmed ORCID: 0000-0002-8622-4632 (2021) Determination of optic axes by corneal topography among Italian, Brazilian and Chinese populations. Photonics, 8 (Visual). p. 61. ISSN 2304-6732, 2304-6732

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Official URL: https://doi.org/10.3390/photonics8020061

Abstract

<jats:p>This study aims to describe a new universal method to identify the relative three-dimensional directions of visual, pupillary, and optical axes of the eye and the angles between them using topography elevation data. The method was validated in a large clinical cohort, and ethnical differences were recorded. Topography elevation data were collected from 1992 normal eyes of 966 healthy participants in Italy, Brazil, and China. The three main axes were defined as follows: optical axis (OA) was defined as the optimal path of light that passes through the ocular system without refraction. The pupillary axis (PA) line was defined using X and Y coordinates of the pupil centre with the chamber depth, in addition to the centre of a sphere fitted to the central 3 mm diameter of the cornea. The visual axis (VA) was taken by its best approximation, the coaxially sighted corneal light reflex. The alpha angle was measured between the VA and OA, and the kappa angle between the VA and PA. The average values of kappa and alpha angles were 3.41 ± 2.84 and 6.04 ± 2.43 in the Italian population, 2.6 ± 1.53 and 5.87 ± 2.3 in the Brazilian population, and 2.09 ± 1.22 and 3.85 ± 1.48 in the Chinese population.</jats:p>

Item Type:	Article
Uncontrolled Keywords:	cornea, topography, optical axis, visual axis, pupillary axis, kappa angle, alpha angle
Depositing User:	Symplectic Admin
Date Deposited:	11 Feb 2021 08:53
Last Modified:	06 Dec 2024 22:14
DOI:	10.3390/photonics8020061
Open Access URL:	http://doi.org/10.3390/photonics8020061
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3115449