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Laura K. Young, Gordon D. Love, Hannah E. Smithson; Going beyond the wavefront: Improved predictions of performance obtained by accounting for the spatial frequency requirements of the task.. Journal of Vision 2012;12(14):19. doi: https://doi.org/10.1167/12.14.19.
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© ARVO (1962-2015); The Authors (2016-present)
Ocular aberrations cause distortions of the image falling on the retina, as characterised by the optical transfer function of the eye. Recent work has shown that good predictions of visual acuity can be made from the wavefront measurement, particularly when the neural contrast sensitivity function is taken into account, as in the visual Strehl ratio for example (Cheng et al., 2004; Marsack et al., 2004; Thibos et al., 2004). We have recently shown that the effect of an aberration on visual performance depends on its type (Young et al., 2011) and is task-specific even for related tasks such as letter recognition and reading (Young et al., 2012). How then might we better understand the wavefront measurement in terms of real-life visual performance? We have tested the correlation between different metrics for predicting visual performance from the wavefront aberration and our experimental data. Letters are typically identified via a narrow spatial frequency band (Solomon & Pelli, 1994), however the centre frequency can change depending on the size of the letter and if it is spatially filtered (Majaj et al., 2002), switching when it is useful to do so (Oruc & Landy, 2009). We show that by additionally accounting for the spatial frequencies mediating letter identification we can better predict changes in performance from the wavefront measurement. Using bandpass noise we masked the spurious resolution that is introduced by an aberration. The pattern of performance improvements suggest that "off-frequency looking" is important when identifying aberrated letters.
Meeting abstract presented at OSA Fall Vision 2012
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