Accuracy and precision of videokeratoscopes for test surfaces
Tang, Wilfred, Collins, Michael J., & Carney, Leo G. (1999) Accuracy and precision of videokeratoscopes for test surfaces. In 8th Scientific Meeting in Optometry, 1–3 July 1999, The University of New South Wales, Australia.
The present study evaluated the accuracy and precision performance of three videokeratoscopes (the Keratron, TMS-1 and PAR systems) in elevation topography with six test surfaces that were designed to challenge each instrument’s ability to measure them. The test surfaces comprised a sphere (r = 7.8 mm), an asphere (r = 7.8 mm, Q = - 0.49), a multicurve (r1 = 7.84 mm, r2 = 7.54, r3 = 7.84, r4 = 7.54, r5 = 7.84), a 5.0 bicurve (r1 = 5.0 mm, r2 = 7.80), a 6.5 bicurve (r1= 6.5 mm, r2 = 7.80) and an 8.5 bicurve (r1= 8.5 mm, r2= 7.80, sag = 50 μm). For the spherical test surface, the root mean square error (RMSE) data showed the instrument accuracies for the Keratron, TMS-1 and PAR systems were 1.64, 2.61 and 20.89 μm, respectively. The standard error for the Keratron system was small (< ± 1 μm) for the same test surface, compared to the standard errors of ± 3 and ± 44 μm for the TMS-1 and PAR systems. Overall, each instrument performed well on certain test surfaces but none of the instruments excelled on all the surfaces. The study has confirmed the high accuracy of the Keratron system in measuring test surfaces such as the sphere, the asphere and the multicurve. The precision of the instrument was the best among the three instruments. The TMS-1 system was slightly less accurate and precise than the Keratron system in elevation topography for the sphere and the asphere surfaces. Of the three instruments, the PAR system has the poorest performance in accuracy and precision.
Impact and interest:
Citation counts are sourced monthly from and citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||Conference Paper|
|Additional Information:||Abstract published in Clinical and Experimental Optometry, 83(2), p. 86|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Vision Science (111303)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Optical Technology (111302)
|Divisions:||Current > Research Centres > Centre for Health Research
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2000 Optometrists Association Australia|
|Deposited On:||21 Jan 2008 00:00|
|Last Modified:||03 Nov 2014 04:13|
Repository Staff Only: item control page