Determination of Optic Axes by Corneal Topography among Italian, Brazilian, and Chinese Populations

Photonics

卷:8

Renato Ambrósio¹  Paolo Vinciguerra²  Riccardo Vinciguerra³  Mohamed Elhalwagy⁴  BernardoT. Lopes⁵  Ashkan Eliasy⁵  Ahmed Elsheikh⁵  Ahmed Abass⁵  Fangjun Bao⁶ 

[1] Department of Ophthalmology, Federal University of São Paulo, São Paulo 04021, Brazil;

[2] Humanitas Clinical and Research Center—IRCCS Rozzano, 20089 Rozzan, Italy;

[3] Humanitas San Pio X Hospital, 20159 Milano, Italy;

[4] Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK;

[5] School of Engineering, University of Liverpool, Liverpool L69 3GH, UK;

[6] School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou 325035, China;

关键词: cornea;    topography;    optical axis;    visual axis;    pupillary axis;    kappa angle;   

DOI  :  10.3390/photonics8020061

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown