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Aiswaryah Radhakrishnan, Carlos Dorronsoro, Susana Marcos; Subjective preference to orientation of an angular bifocal IOL design. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3126.
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© ARVO (1962-2015); The Authors (2016-present)
Angularly segmented multifocal designs visually outperform other symmetric multifocal designs. Unlike concentric designs, the actual orientation of the angular patterns may influence the performance of these lenses in real eyes. We studied visual and perceptual performance for different orientations of an angularly segmented lens, simulated optically using a simultaneous vision simulator.
Twenty cyclopleged subjects (21 – 62 yrs) performed psychophysical tasks for 8 orientations of M-Plus© lens (Oculentis) at different optical vergences (0D, +1.5D and +3D). The IOL was simulated in a two-channel simultaneous vision simulator with a Spatial Light Modulator. High Contrast Decimal Visual Acuity (HCVA) was measured using a tumbling E target and pattern preference was assessed using a face image presented through 360 random pairs of different lens orientations (in 45 deg steps). The preferred orientation was calculated as the orientation of the centroid of the polygon encompassing the data for eight orientations in a polar plot, at each distance. Optical predictions of orientation preference were obtained from the VSOTF calculated using subjects’ ocular aberrations and multifocal pattern at each orientation and implementing an ideal observer model based on the differential VSOTF values.
HCVA was better for far than at near (HCVAf=0.63±0.06, HCVAn=0.56±0.07, p<0.001) and did not differ significantly across orientations (p=0.42). Significant differences in perceptual quality were found across pattern orientations (p=0.048); 8 subjects showed strong orientation preferences. The mean difference in the optimal orientation between far and near was 27±22 degrees and was not significant (p=0.66). Horizontal orientation (near segment at 0/180±45deg) was preferred by 14 subjects at far and 13 subjects at near. Strong significant correlation was found between measured and optically predicted pattern preference at far and near distances (rf=0.71, rn=0.62, p<0.0001). The mean difference in centroid location between measurement and prediction was 28±29 deg at far and 36±28 deg at near distances.
Perceptual quality of an angularly segmented multifocal lens varies with pattern orientation. The preferred orientation is driven by interactions of the design with optical aberrations of the eye. Simultaneous Vision Simulator can be used to measure the preferred orientation of the lens and optimize lens performance.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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