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Len Zheleznyak, Ramkumar Sabesan, Scott MacRae, Geunyoung Yoon; Optimizing Modified Monovision to Improve Binocular Through-Focus Visual Performance. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6328.
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© ARVO (1962-2015); The Authors (2016-present)
To improve binocular through-focus visual performance by optimizing modified monovision, specifically the Zernike primary spherical aberrations (SA) in both eyes and anisometropia
To optimize modified monovision, monocular through-focus RIQ was first estimated by calculating the correlation coefficient of convolved images. Binocular through-focus RIQ was attained by selecting the better of the two monocular values at each through-focus position. Area under the binocular RIQ between 0 and 2.5D after shifting the peak of RIQ to 0D was calculated to represent overall binocular RIQ for modified monovision parameters: anisometropia (up to 2.0D at 0.5D step) and Zernike primary SA in the dominant and non-dominant eyes (-0.4 to +0.4μm at 0.1μm step). From this analysis, the modified monovision approach that maximized through-focus RIQ was chosen for vision testing in 3 cyclopleged subjects. Visual performance was measured with a binocular adaptive optics vision simulator viewing through a 4mm pupil. Through-focus visual acuity (VA) (0 to 3.5D at 0.5D step) was measured in all subjects and two-line stereoacuity was measured in one subject at 0 and 1D. SA and anisometropia for modified monovision were induced after subjects’ native aberrations in both eyes were corrected. Modified monovision was compared with traditional monovision (TMV) with 1.5D of anisometropia. A VA threshold of -0.18logMAR was used to estimate the depth of focus (DoF).
Through-focus binocular VA was well predicted by the image convolution based RIQ metric (R2=0.85) that provided considerably better correlation than conventional RIQ metrics. The modified monovision design maximizing through-focus RIQ had 1.5D anisometropia and +0.1μm and -0.4μm SA in the dominant and non-dominant eyes, respectively. Modified monovision showed a significant benefit in VA at 0.5D and near (2.0 to 3.5D) by an average of 0.15+0.05logMAR compared to TMV. VA degraded at 1.5D in modified monovision as compared to TMV (-0.19+0.06 and -0.31+0.11logMAR, respectively). DoF with modified monovision and TMV was 3.41+0.08 and 2.77+0.03D, respectively. Stereoacuity at 0D was improved significantly in modified monovision as compared to TMV (104 and 218 arc sec, respectively) without compromising performance at 1D (111 and 108 arc sec, respectively).
The image convolution based RIQ metric reliably predicts binocular visual performance in the presence of SA and large amounts of defocus, facilitating the effective optimization of modified monovision. Combining primary SA of different signs and magnitudes in each of the two eyes in modified monovision has the potential to substantially improve through-focus VA and stereoacuity as compared to TMV.
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