June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
Influence of aberration-induced blur on contrast sensitivity: comparison of different optotype sizes
Author Affiliations & Notes
  • Jens Buehren
    Dept of Ophthalmology, Goethe University Frankfurt, Frankfurt am Main, Germany
  • Hendrik Jungnickel
    SciTec Department, Ernst Abbe University of Applied Sciences, Jena, Germany
    Institute for Apllied Optics, Schiller University Jena, Jena, Germany
  • Wolfgang Raab
    Dept of Ophthalmology, Goethe University Frankfurt, Frankfurt am Main, Germany
  • Daniel Weigel
    Institute for Apllied Optics, Schiller University Jena, Jena, Germany
  • Michael Gebhardt
    SciTec Department, Ernst Abbe University of Applied Sciences, Jena, Germany
  • Richard Kowarschik
    Institute for Apllied Optics, Schiller University Jena, Jena, Germany
  • Thomas Kohnen
    Dept of Ophthalmology, Goethe University Frankfurt, Frankfurt am Main, Germany
  • Footnotes
    Commercial Relationships Jens Buehren, None; Hendrik Jungnickel, None; Wolfgang Raab, None; Daniel Weigel, None; Michael Gebhardt, None; Richard Kowarschik, None; Thomas Kohnen, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 1280. doi:
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      Jens Buehren, Hendrik Jungnickel, Wolfgang Raab, Daniel Weigel, Michael Gebhardt, Richard Kowarschik, Thomas Kohnen; Influence of aberration-induced blur on contrast sensitivity: comparison of different optotype sizes. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1280.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: To compare the decrease of contrast sensitivity (CS) due to defocus and higher-order aberration (HOA) blur measured with optotypes of different size.

Methods: Thirty-three emmetropic healty volunteers were included. In a first experiment (defocus blur), CS was measured in 31 eyes. Experimental fogging was performed with spherical trial lenses of 0, +0.25, +0.5 and +0.75 diopters (D). In a second experiment (HOA blur), CS was measured in 3 eyes at an adaptive optics (AO) visual simulator. Besides the correction of lower-order aberrations (LOA) and full correction, subjects were presented 6 wavefront errors of different blur strength and characteristics (3 keratoconus eyes, 3 post-LASIK eyes). In total, 8 different wavefront errors with a VSOTF (visual Strehl ratio based on the optical transfer function) range of -0.05 to -1.70 log units were presented. In both experiments, CS was measured with Landolt rings of 1.3 and 0.3 logMAR using FrACT software. The impact of defocus blur (D) or HOA blur (VSOTF) on CS was assessed using linear regression analysis. The regression coefficient b and the coefficient of determination R2 reflect the sensitivity of the CS contrast test to aberration-induced blur.

Results: Experiment 1: Unfogged photopic CS was 1.93±0.06 logCS (1.3 logMAR) and 1.56±0.05 logCS (0.3 logMAR). Regression coefficients were higher for the 0.3 logMAR (b=-0.88, R2=0.70) than for the 1.3 logMAR Landolt ring (b=-0.39, R2=0.28). Experiment 2: CS was 1.98±0.17 (0.3 logMAR optotype: 0.95±0.14) log units with full AO correction. Also in this experiment, CS was more sensitive to optical blur if measured Landolt rings of 0.3 logMAR (b=0.63, R2=0.74) compared to those of 1.3 logMAR (b=0.34, R2=0.34).

Conclusions: CS tests with large optotypes such as the Pelli-Robson test may not pick up subtle, yet notable aberration-induced changes in retinal image quality. Therefore, for the assessment of effects of optical aberrations, CS testing should be performed at higher spatial frequencies (e.g., 0.3 logMAR Landolt ring).

Keywords: 478 contrast sensitivity • 626 aberrations • 684 refractive surgery: optical quality  
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