Investigation of the unfused cross cylinder test as an alternative method for the determination of spherical distance refraction end points

African Vision and Eye Health


 
 
Field Value
 
Title Investigation of the unfused cross cylinder test as an alternative method for the determination of spherical distance refraction end points
 
Creator Makgaba, Nkalebetja T. Mathebula, Solani D.
 
Subject — duochrome; bichrome; unfused cross cylinder; spherical end point; chromatic aberration
Description Background: The duochrome test is commonly used to refine the final sphere in refraction at different stages of a subjective refraction. The unfused cross cylinder test is mainly used to determine the near reading addition with a combination of astigmatic lenses.Aim: To investigate if the unfused cross cylinder test can be adapted for distance in finding the spherical end point for distance prescription.Setting: The study was conducted at an Optometry Clinic, University of Limpopo, South Africa.Methods: Fifty-one non-presbyopic subjects aged between 18 and 25 years were examined. The duochrome and unfused cross cylinder examinations were performed monocularly under normal (bright) and dim room illumination.Results: There was no significant difference in the spherical end point determined with either the duochrome or unfused cross cylinder tests (p ≥ 0.05). The mean spherical end points as determined with the duochrome test were −0.09 ± 0.39 diopre sphere (DS) (range: −0.20 to 0.12 dioptres [D]) in bright room illumination and −0.05 ± 0.38 DS (range: −0.16 D to 0.05 D) in dim illumination. The mean spherical end points for the unfused cross cylinder tests were −0.29 ± 0.39 DS (range: −0.18 D to 0.40 D) and −0.32 ± 0.43 DS (range: –0.44 D to –0.19 D) in room dim illuminations, respectively.Conclusion: The unfused cross cylinder test results as performed in this study may provide an accurate measurement of the spherical end point in a young adult population. We recommend the unfused cross cylinder test to be used in normal (bright) room illumination as an alternative to the duochrome test in the determination of distance refractive error.
 
Publisher AOSIS
 
Contributor
Date 2020-09-30
 
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — —
Format text/html application/epub+zip text/xml application/pdf
Identifier 10.4102/aveh.v79i1.514
 
Source African Vision and Eye Health; Vol 79, No 1 (2020); 5 pages 2410-1516 2413-3183
 
Language eng
 
Relation https://avehjournal.org/index.php/aveh/article/view/514/1304 https://avehjournal.org/index.php/aveh/article/view/514/1303 https://avehjournal.org/index.php/aveh/article/view/514/1305 https://avehjournal.org/index.php/aveh/article/view/514/1302
 
Coverage — — —
Rights Copyright (c) 2020 Nkalebetja T. Makgaba, Solani D. Mathebula https://creativecommons.org/licenses/by/4.0