Measurement of Refractive Errors in Young Myopes Using the COAS Shack-Hartmann Aberrometer

Salmon, Thomas; West, Roger W.; Gasser, Wayne; Kenmore, Todd

doi:10.1097/00006324-200301000-00003

Cited by 96 publications

(89 citation statements)

References 26 publications

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“…There have been several other studies of wavefront measurement device reproducibility. 13,14,22 These have included the Tracey device and the WaveScan system (VISX, Santa Clara, CA, USA) as well as a method using Hartmann-Shack techniques. These studies found that the standard deviation of the conventional refractive index measured by wavefront devices was between 0.1 and 0.5D.…”

Section: Comparison Of Two Wavefront Devices D-ug Bartsch Et Almentioning

confidence: 99%

Comparison of laser ray-tracing and skiascopic ocular wavefront-sensing devices

Bartsch

Bessho

Gomez

et al. 2007

Eye

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Purpose To compare two wavefront-sensing devices based on different principles. Methods Thirty-eight healthy eyes of 19 patients were measured five times in the reproducibility study. Twenty eyes of 10 patients were measured in the comparison study. The Tracey Visual Function Analyzer (VFA), based on the ray-tracing principle and the Nidek optical pathway difference (OPD)-Scan, based on the dynamic skiascopy principle were compared. Standard deviation (SD) of root mean square (RMS) errors was compared to verify the reproducibility. We evaluated RMS errors, Zernike terms and conventional refractive indexes (Sph, Cyl, Ax, and spherical equivalent). Results In RMS errors reading, both devices showed similar ratios of SD to the mean measurement value (VFA: 57.5711.7%, OPD-Scan: 53.9710.9%). Comparison on the same eye showed that almost all terms were significantly greater using the VFA than using the OPD-Scan. However, certain high spatial frequency aberrations (tetrafoil, pentafoil, and hexafoil) were consistently measured near zero with the OPD-Scan. Conclusion Both devices showed similar level of reproducibility; however, there was considerable difference in the wavefront reading between machines when measuring the same eye. Differences in the number of sample points, centration, and measurement algorithms between the two instruments may explain our results.

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Section: Comparison Of Two Wavefront Devices D-ug Bartsch Et Almentioning

confidence: 99%

Comparison of laser ray-tracing and skiascopic ocular wavefront-sensing devices

Bartsch

Bessho

Gomez

et al. 2007

Eye

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“…It is important to note that in order to compare two sphero-cylinders (sphere, cylinder, and axis) one needs to transform each of them into three orthogonal refractive power vector components M, J0 and J45, where M denotes the mean spherical power while J0 and J45 describe astigmatic components at 0 and 45 degrees, respectively [21]. Since measurement errors are present both in subjective and objective assessments of vision quality, orthogonal linear regression was used to establish correlation between subjectively assessed power vector components and their objectively assessed counterparts.…”

mentioning

confidence: 99%

A subjective refraction-based assessment of image quality metric

Iskander¹

2011

Photon. Lett. Poland

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“…Mit dem Shack-Hartmann-Aberrometer stand für diese Arbeit ein zuverlässiges und leistungsfähiges Messgerät zur Verfügung, mit dem sich die optischen Aberrationen des menschlichen Auges gut und genau wiederholbar beschreiben lassen (Salmon et al 1998, Thibos und Hong 1999, Salmon et al 2003. Cheng et al (2003b) fanden, dass akkurates und wiederholbares Messen der Aberrationen bis vierter Ordnung mit dem COAS-Aberrometer gut möglich ist und dass Störungen der Messungen durch das Gerät selbst sehr gering sind.…”

Section: Gerätetechnologieunclassified