The validity and reliability of the handheld SW-100 autokeratometer
African Vision and Eye Health
Field | Value | |
Title | The validity and reliability of the handheld SW-100 autokeratometer | |
Creator | Iyamu, Eghosasere Amiebenomo, O. Mary-Anne | |
Description | Background: The agreement of new instruments or clinical tests with other instruments or tests defines the possibility of these being used interchangeably.Aim: To investigate the validity and reliability of the SW-100 autokeratometer using a Bausch Lomb (BL) keratometer as the ‘gold standard’. Methods: Eighty subjects (80 right eyes) aged between 21 and 38 years were recruited. For intra-test repeatability, two measurements of the corneal radius of curvature were taken with the SW-100 and BL keratometers. Forty of the 80 subjects participated in the inter-test repeatability measurement.Results: Corneal radius of curvature was found to be statistically different between the two instruments (p 0.001), with the SW-100 providing slightly flatter values of 0.11 mm and 0.05 mm for the horizontal and vertical meridians, respectively, than the BL keratometer. The average corneal curvature was 0.07 mm flatter with the SW-100 autokeratometer than with the BL device. Agreement between the SW-100 and BL keratometers’ axes was 45% within ± 5°, 60.3% within ± 10°, 78.8% within ± 15°, 80.3% within ± 20°, and 88.7% within ± 40°. Intertest repeatability was better for the BL device than the SW-100 and showed no significant difference between the two sessions. Both instruments demonstrated comparable intrasession repeatability. As such, both instruments were comparatively reliable (per coefficients of repeatability). The range of limits of agreement of ± 0.14 mm (horizontal meridian) and ± 0.17 mm (vertical meridian) between the SW-100 and BL devices showed good agreement.Conclusion: The results suggest that the SW-100 autokeratometer is a reliable and objective instrument that, however, provides flatter radii of curvature measurements than the BL keratometer. A compensating factor incorporated into the instrument could reduce the difference between the two instruments and make them more interchangeable. | |
Publisher | AOSIS | |
Date | 2015-07-23 | |
Identifier | 10.4102/aveh.v74i1.26 | |
Source | African Vision and Eye Health; Vol 74, No 1 (2015); 5 pages 2410-1516 2413-3183 | |
Language | eng | |
Relation |
The following web links (URLs) may trigger a file download or direct you to an alternative webpage to gain access to a publication file format of the published article:
https://avehjournal.org/index.php/aveh/article/view/26/386
https://avehjournal.org/index.php/aveh/article/view/26/387
https://avehjournal.org/index.php/aveh/article/view/26/388
https://avehjournal.org/index.php/aveh/article/view/26/350
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