Accuracy and precision of videokeratoscopes for test surfaces
(2000) Accuracy and precision of videokeratoscopes for test surfaces. Clinical & Experimental Optometry 83(2):86.
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Abstract
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.
| Item Type: | Journal Article |
|---|---|
| Status: | Published |
| Subjects: | 320000 Medical and Health Sciences > 320900 Optometry 320000 Medical and Health Sciences > 321000 Clinical Sciences > 321016 Opthalmology and Vision Science 320000 Medical and Health Sciences > 320900 Optometry > 320901 Optical Technology |
| ID Code: | 12145 |
| Deposited By: | Moyle, Claire D |
| Deposited On: | 21 January 2008 |
| Alternative Locations: | http://www.optometrists.asn.au/ceo |
| Copyright Owner: | Copyright 2000 Optometrists Association Australia |
| Additional Information: | The contents of this journal from 1998 to 2005 can be freely accessed online via the journal’s web page (see hypertext link). |