Average paraxial power of a lens and visual acuity.

Kaye, Stephen B ORCID: 0000-0003-0390-0592, Surti, Jamila and Wolffsohn, James S
(2023) Average paraxial power of a lens and visual acuity. Scientific reports, 13 (1). p. 7118.

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To provide a solution for average paraxial lens power (A<sub>p</sub>P) of a lens. Orthogonal and oblique sections through a lens of power [Formula: see text] were reduced to a paraxial representation of lens power followed by integration. Visual acuity was measured using lenses of different powers (cylinders of - 1.0 and - 2.0D) and axes, mean spherical equivalent (MSE) of S + C/2, A<sub>p</sub>P and a toric correction, with the order of correction randomised. A digital screen at 6 m was used on which a Landolt C with crowding bars was displayed for 0.3 s before vanishing. The general equation for a symmetrical lens of refractive index (n), radius of curvature R, in medium of refractive index n1, through orthogonal ([Formula: see text]) and oblique meridians ([Formula: see text]) as a function of the angle of incidence ([Formula: see text]) reduces for paraxial rays ([Formula: see text]) to [Formula: see text]. The average of this function is [Formula: see text] providing a solution of [Formula: see text] for A<sub>p</sub>P.For central (p = 0.04), but not peripheral (p = 0.17) viewing, correction with A<sub>p</sub>P was associated with better visual acuity than a MSE across all tested refractive errors (p = 0.04). These findings suggest that [Formula: see text] may be a more inclusive representation of the average paraxial power of a cylindrical lens than the MSE.

Item Type: Article
Uncontrolled Keywords: Humans, Refractive Errors, Astigmatism, Refraction, Ocular, Lenses, Visual Acuity
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Life Courses and Medical Sciences
Depositing User: Symplectic Admin
Date Deposited: 21 Jun 2023 08:29
Last Modified: 21 Jun 2023 08:29
DOI: 10.1038/s41598-023-34010-4
Open Access URL: https://doi.org/10.1038/s41598-023-34010-4
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3171172