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Yue Shi, Xin Wei, Ayeswarya Ravikumar, Raymond A. Applegate; Changes In Log Visual Strehl Predicts Changes In Visual Acuity. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2814. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
At ARVO 2010 we reported a linear relationship between logMAR acuity and the retinal image quality metric log visual Strehl (log VS) (R2 = 0.987) from scaling the wavefront error (WFE) of one normal subject up and down. The purpose of this study is to extend this work and determine if change in log VS predicts change in visual acuity when the underlying WFE defining each level of log VS is different (not simply a scaled version of one single underlying WFE).
Ten different WFEs over a 3mm entrance pupil having approximately equal steps of log VS ranging from 0.00 to -1.57 served as the WFEs of interest. For each of the 10 different WFEs, three unique letter arrangement of a 100% contrast 11 line log MAR acuity chart were convolved with the resulting point spread function to generate 30 aberrated charts. In addition, 3 diffraction limited reference charts were generated. One eye of each of three healthy normal subjects was dilated (1% tropicamide) and trial frame refracted through a 3mm artificial pupil placed in a trial frame. Each subject’s log MAR acuity was measured using each of the aberrated charts (300 cd/m2) and the 3 reference charts up to the 5th letter miss through the 3 mm artificial pupil. Change in log MAR acuity was linearly regressed against the change in log VS.
The linear regression analysis revealed log MAR = -0.18 x log VS + 0.06 (R2 = 0.774). Change in log VS is a good predictor of change in acuity regardless of whether the underlying form of the WFE is the same or different.
Change in the retinal image quality metric log VS is well correlated with change in visual acuity regardless of the underlying WFE.
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