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Aberrometer

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James S. Wolffsohn – One of the best experts on this subject based on the ideXlab platform.

  • validity of a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Poster Purpose: A study to validate a prototype Hartmann-Shack (HS) wavefront Aberrometer. Methods: The dynamic range was assessed using a calibrated model eye. It was validated against a conventional HS-Aberrometer (Topcon KR1W) in 75 eyes using both instruments in random order. Additionally, intra-sessional repeatability was tested. Results: The Aberrometer showed a large dynamic range of +21.0 D to −25.0 D. It was comparable to a conventional HS Aberrometer for spherical-equivalent SE (MD ± 95% CI: 0.02 ± 0.49D; correlation: r = 0.995, p < 0.001), astigmatic components (J0: 0.02 ± 0.15D; r = 0.977, p < 0.001; J45: 0.03 ± 0.28; r = 0.666, p < 0.001) and HOAs RMS (0.02 ± 0.20D; r = 0.620, p < 0.001). Intra-sessional repeatability correlation was also excellent (SE = 1.000, p < 0.001; astigmatic-components J0 = 0.998, p < 0.001, J45 = 0.980, p < 0.01; HOAs RMS = 0.961, p < 0.001). Conclusions: This study confirms the validity of the prototype Aberrometer. The prototype Aberrometer can measure continuously to provide direct feedback of the optical status of the eye during surgery.

  • Validity of a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Poster Purpose: A study to validate a prototype Hartmann-Shack (HS) wavefront Aberrometer. Methods: The dynamic range was assessed using a calibrated model eye. It was validated against a conventional HS-Aberrometer (Topcon KR1W) in 75 eyes using both instruments in random order. Additionally, intra-sessional repeatability was tested. Results: The Aberrometer showed a large dynamic range of +21.0 D to −25.0 D. It was comparable to a conventional HS Aberrometer for spherical-equivalent SE (MD ± 95% CI: 0.02 ± 0.49D; correlation: r = 0.995, p 

  • intraoperative prediction of refractive error using a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Purpose: To ascertain the agreement level between intra-operative refraction using a prototype surgical Hartmann-Shack Aberrometer and subjective refraction a month later. Methods: Fifty-four consecutive patients had their pseudophakic refractive measured with the Aberrometer intra-operatively at the end of their cataract surgery. A masked optometrist performed subjective refraction 4 weeks later. The two sets of data were then analysed for correlation. Results: The mean spherical equivalent was −0.14 ± 0.37 D (Range: −1.41 to +1.72 D) with the prototype Aberrometer and −0.34 ± 0.32 (−1.64 to +1.88 D) with subjective refraction. The measurements positively correlated to a very high degree (r =+0.81, p < 0.01). In 84.3% of cases the two measurements were within 0.50D of each other. Conclusion: The Aberrometer can verify the aimed refractive status of the eye intraoperatively to avoid a refractive surprise. The Aberrometer is a useful tool for real time assessment of the ocular refractive status.

Uday K. Bhatt – One of the best experts on this subject based on the ideXlab platform.

  • validity of a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Poster Purpose: A study to validate a prototype Hartmann-Shack (HS) wavefront Aberrometer. Methods: The dynamic range was assessed using a calibrated model eye. It was validated against a conventional HS-Aberrometer (Topcon KR1W) in 75 eyes using both instruments in random order. Additionally, intra-sessional repeatability was tested. Results: The Aberrometer showed a large dynamic range of +21.0 D to −25.0 D. It was comparable to a conventional HS Aberrometer for spherical-equivalent SE (MD ± 95% CI: 0.02 ± 0.49D; correlation: r = 0.995, p < 0.001), astigmatic components (J0: 0.02 ± 0.15D; r = 0.977, p < 0.001; J45: 0.03 ± 0.28; r = 0.666, p < 0.001) and HOAs RMS (0.02 ± 0.20D; r = 0.620, p < 0.001). Intra-sessional repeatability correlation was also excellent (SE = 1.000, p < 0.001; astigmatic-components J0 = 0.998, p < 0.001, J45 = 0.980, p < 0.01; HOAs RMS = 0.961, p < 0.001). Conclusions: This study confirms the validity of the prototype Aberrometer. The prototype Aberrometer can measure continuously to provide direct feedback of the optical status of the eye during surgery.

  • Validity of a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Poster Purpose: A study to validate a prototype Hartmann-Shack (HS) wavefront Aberrometer. Methods: The dynamic range was assessed using a calibrated model eye. It was validated against a conventional HS-Aberrometer (Topcon KR1W) in 75 eyes using both instruments in random order. Additionally, intra-sessional repeatability was tested. Results: The Aberrometer showed a large dynamic range of +21.0 D to −25.0 D. It was comparable to a conventional HS Aberrometer for spherical-equivalent SE (MD ± 95% CI: 0.02 ± 0.49D; correlation: r = 0.995, p 

  • intraoperative prediction of refractive error using a prototype surgical Aberrometer
    Clinical and Experimental Ophthalmology, 2014
    Co-Authors: Uday K. Bhatt, Sunil Shah, Harminder S Dua, James S. Wolffsohn
    Abstract:

    Purpose: To ascertain the agreement level between intra-operative refraction using a prototype surgical Hartmann-Shack Aberrometer and subjective refraction a month later. Methods: Fifty-four consecutive patients had their pseudophakic refractive measured with the Aberrometer intra-operatively at the end of their cataract surgery. A masked optometrist performed subjective refraction 4 weeks later. The two sets of data were then analysed for correlation. Results: The mean spherical equivalent was −0.14 ± 0.37 D (Range: −1.41 to +1.72 D) with the prototype Aberrometer and −0.34 ± 0.32 (−1.64 to +1.88 D) with subjective refraction. The measurements positively correlated to a very high degree (r =+0.81, p < 0.01). In 84.3% of cases the two measurements were within 0.50D of each other. Conclusion: The Aberrometer can verify the aimed refractive status of the eye intraoperatively to avoid a refractive surprise. The Aberrometer is a useful tool for real time assessment of the ocular refractive status.

Rudy M.m.a. Nuijts – One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of the Comparability and Repeatability of Four Wavefront Aberrometers
    Investigative ophthalmology & visual science, 2011
    Co-Authors: Nienke Visser, Tos T. J. M. Berendschot, Frenne Verbakel, Annelie N. Tan, John De Brabander, Rudy M.m.a. Nuijts
    Abstract:

    PURPOSE To compare total ocular aberrations and corneal aberrations identified with four different Aberrometers and to determine the repeatability and interobserver variability. METHODS In this prospective comparative study, 23 healthy subjects underwent bilateral examination with four Aberrometers: the Irx3 (Hartmann-Shack; Imagine Eyes, Orsay, France), Keratron (Hartmann-Shack; Optikon, Rome Italy), iTrace (ray-tracing; Tracey Technologies, Houston, TX), and OPD-Scan (Automated Retinoscopy; Nidek, Gamagori, Japan). Six images per eye were obtained. Second-, third- and fourth-order spherical aberrations were exported for 5.0-mm pupils. RESULTS Significant differences in measurements were found for several total ocular aberrations (defocus [2,0], astigmatism [2,2], trefoil [3,-3], trefoil [3,3], and spherical aberration [4,0]) and corneal aberrations (defocus [2,0] and astigmatism [2,2]). The Irx3 showed the highest repeatability in measuring total ocular aberrations, followed by the Keratron, OPD-Scan, and iTrace. The repeatability of the corneal aberration measurements was highest for the iTrace, followed by the Keratron and OPD-Scan. The OPD-Scan showed a lower interobserver variability, compared with the Irx3, Keratron, and iTrace. CONCLUSIONS Total ocular and corneal aberrations are not comparable when measured with different Aberrometers. Hartmann-Shack Aberrometers showed the best repeatability for total ocular aberrations and iTrace for corneal aberrations. It would be worthwhile in the future to evaluate Aberrometers in patients with more aberrant eyes.

  • Repeatability and validity of Zywave Aberrometer measurements
    Journal of cataract and refractive surgery, 2002
    Co-Authors: Willem J Hament, Vaisjaly A Nabar, Rudy M.m.a. Nuijts
    Abstract:

    Abstract Purpose To study the repeatability of Zywave Aberrometer (Bausch & Lomb) measurements and compare the measurements with those of subjective refraction and noncycloplegic and cycloplegic autorefractions in a clinical setting. Setting Department of Ophthalmology, University Hospital Maastricht, Maastricht, The Netherlands. Methods Subjective manifest refraction, noncycloplegic autorefraction, cycloplegic autorefraction, and Zywave Aberrometer measurements were performed in 20 eyes of 20 myopic patients. Three consecutive Zywave measurements were performed with and without dilation of the pupil. The mean difference and 95% limits of agreement among the measurement methods were determined for dilated and 3.5 mm pupils. The repeatability coefficient of the Zywave Aberrometer measurements was determined. Results The mean differences in spherical equivalent (SE), sphere, and cylinder between subjective refraction and Zywave predicted phoropter refraction (PPR) with a dilated pupil were −1.10 diopters (D) ± 0.46 (SD) (P Conclusions Subjective refraction measurements are slightly more myopic than cycloplegic autorefraction measurements. With a dilated pupil, the Zywave measurements were significantly more myopic than subjective refractions and even more myopic than cycloplegic autorefractions. Zywave measurements and subjective refractions were in better agreement with a 3.5 mm pupil. The repeatability of Zywave Aberrometer measurements is adequate for lower-order aberrations.