Positions of Ocular Geometrical and Visual Axes in Brazilian, Chinese and Italian Populations.

Publisher: Informa Healthcare Country of Publication: England NLM ID: 8104312 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1460-2202 (Electronic) Linking ISSN: 02713683 NLM ISO Abbreviation: Curr Eye Res Subsets: MEDLINE

Publication: London : Informa Healthcare
Original Publication: London : IRL Press, [c1981-

Cornea/*anatomy & histology ; Corneal Topography/*methods ; Eye Movements/*physiology ; Vision, Binocular/*physiology; Adult ; Brazil ; China ; Female ; Head Movements/physiology ; Healthy Volunteers ; Humans ; Italy ; Male ; Retrospective Studies ; Young Adult

Purpose: To identify the relative positions of geometrical and visual axes of the eye and present a method to locate the visual center when the geometrical axis is taken as a reference.
Methods: Topography elevation data was collected using a Pentacam HR ® topographer from 2040 normal eyes of 1020 healthy participants in Brazil, China and Italy. A three-dimensional, rotation algorithm, a first-order Zernike polynomial fit and a nonlinear least-squares error function was used within an optimization function to locate the geometrical axis and the visual center of each eye.
Results: The right eyes of participants were significantly more tilted than left eyes throughout the topography scanning process (p < 0.001). The visual centers were always located in the nasal-superior quadrant, although the visual centers of fellow eyes were not symmetrically located. Mean distances between the visual center and the geometrical center in right eyes were 0.8 ± 0.29 mm, 0.56 ± 0.18 mm and 0.91 ± 0.34 mm among Brazilian, Chinese and Italian participants, respectively, and located at angular positions of 38.7 ± 24.5°, 23.0 ± 29.8° and 23.1 ± 28.1° from the nasal side. However, in left eyes, mean distances were 0.76 ± 0.33 mm, 0.45 ± 0.12 mm and 0.75 ± 0.33 mm at polar angles from the nasal side of 59.3 ± 29.0°, 50.6 ± 44.5° and 61.8 ± 34.1°, respectively.
Conclusions: Fellow eyes do not perform similarly during the fixation process, with right eyes tending to tilt more than left eyes, and the visual centers of the fellow eyes positioned differently relative to the geometrical centers.

Keywords: Cornea; leveling the eye; optical axis; topography; visual axis

Date Created: 20180717 Date Completed: 20191022 Latest Revision: 20191022

20240105

10.1080/02713683.2018.1500609

30009634