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

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