Purchase this article with an account.
Carlos Dorronsoro, Aiswaryah Radhakrishnan, Pablo de Gracia, Lucie Sawides, José Ramón Alonso-Sanz, Daniel Cortés, Susana Marcos; Visual testing of segmented bifocal corrections with a compact simultaneous vision simulator. Invest. Ophthalmol. Vis. Sci. 2014;55(13):781.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate optical quality and visual perception with bifocal simultaneous vision corrections with different pupil segmentation patterns (PSPs).
Fourteen different PSPs with balanced far and near areas (+3.0 D add), arranged in different angular/radial distributions, were evaluated in optical simulations and in visual experiments. The visual experiments were performed on a modified simultaneous vision simulator that introduced PSPs by means of adjustable polarization patterns projected through two focusing channels. Subjects had to score their perceived quality (PQ) over successive face images (0.75 deg) degraded with different PSPs. 105 pairs (all combinations of 14) were presented randomly under cycloplegia (6-mm artificial pupil) for far, near and intermediate vision, and repeated 3 times for each of the 5 subjects. Optical aberrations were measured using custom Hartmann-Shack aberrometry. Through focus optical quality (OQ, in terms of Strehl Ratio) was calculated using Fourier optics for each PSP and each eye.
The different PSPs on a simulated diffraction-limited eye did not produce relevant differences (<3%) in OQ. However, the presence of real aberrations induced strong differences in OQ across PSPs (factors 2 to 10, depending on the subject). All subjects showed significant differences in PQ (p<0.05) with most (56% on average) of the PSPs, typically changing between far and near. Although OQ and PQ across PSPs were not highly correlated (r: 0.3-0.76; with p<0.05 in 2 subjects), in 4/5 subjects the PSP producing the best OQ also produced the highest PQ, both for far and near. In one subject, the best scored PSP was not predicted from optics, indicating neural effects weighting the visual response. Asymmetries in the wave aberration were generally related to higher scores in angularly segmented patterns (with a strong orientation bias).
Significant perceptual differences were found across the different far/near pupillary distributions of bifocal corrections, which varied across subjects and distances. The visual responses can be predicted to a large extent from the differences in the ocular aberrations. However, a two-channel simultaneous vision simulator, considering both optical aberrations and potential neural effects, allows subjective validation of the bifocal patterns producing the best visual quality in each patient.
This PDF is available to Subscribers Only