Presbyopia, the loss of the ability to focus on close objects, affects 100% of the population over 45 years of age. There are more and more corrections of presbyopia, beyond the standard progressive addition near vision glasses, including monovision solutions and multifocal solutions, in the form of contact lenses (LC), intraocular lenses (IOL) or refractive surgery ( CR).

In monovision, one eye is corrected for far distance and the other for near distance to provide functional vision at all distances. However, with this solution one eye is always out of focus. Monovision is based on the brain selectively suppressing out-of-focus images from one eye, using images from the eye that is in focus. Despite some disadvantages caused by interocular blur difference, such as loss of depth discrimination, monovision correction is still the most popular solution to correct presbyopia without glasses.

Alternatively, Simultaneous View creates an overlay of image components with different amounts of blur but with similar content, position, and magnification. Typically, simultaneous vision multifocal intraocular lenses (multifocal IOLs, M-IOLs) are based on diffractive optics, refractive optics or a hybrid approach, while multifocal LCs (M-CLs) tend to be based on rotationally zonal refractive designs. symmetrical, with one part of the pupil dedicated to distance and another to closeness (either in the center or on the periphery). In general, near and far functionality (sometimes also intermediate distances) is achieved at the expense of a certain reduction in visual quality at all distances.

Typically, the quality of vision provided by multifocal lenses, monovision, and combined strategies (i.e. modified monovision in which the dominant eye is corrected with a single vision lens from distance and the non-dominant eye is corrected with a distance lens multifocal) is assessed by visual acuity (VA) at various distances or by blur curves. But it is well known that high contrast visual acuity is a limited descriptor of the quality of vision.

The quality of vision is, in fact, multifactorial, and is highly dependent on visual conditions that affect luminance, pupil diameter, and the spatial content and contrast of the visual world.

In this work, we present for the first time a perceived visual quality test (Multifocal Acceptance Score to Evaluate Vision, MAS-2EV) that combines the systematicity and accessibility of tests performed using visual screens in the clinic (such as visual acuity), with the multicomponent description of the visual world that is collected in the questionnaires. In the MAS-2EV, the patient scores natural images that represent scenes that can be found in daily life (day and night, near and far distances, and stereoscopic vision).

The metric can be applied to patients already implanted with a multifocal intraocular lens, or fitted with contact lenses of various designs, similar to the indicated visual acuity tests or questionnaires. However, the biggest advance of the new metric is based on the possibility of performing these tests before the operation or the placement of real contact lenses in the eye. Preoperative or pre-fitting simulations are now possible with the use of visual simulators.
In the present study, four binocular presbyopia corrections (bilateral monofocal distance corrections, monovision, modified monovision, and bilateral bifocal corrections) were evaluated using the MAS-2EV.

Adaptive optics visual simulators, typically based on deformable mirrors or spatial light modulators, have been used to reproduce various multifocal lens designs. On the other hand, SimVis Gekko (SimVis, 2EyesVision), a binocular through-view visual simulator, with a wide field of view (> 20 °), and is aimed at potential IOL and LC-M patients. SimVis Gekko simulates multifocal corrections using tunable lenses that operate with rapid periodic variations in optical power at speeds greater than human perception, generating apparently static and programmable multifocal images on the patient's retina

We have verified that the MAS-2EV has sufficient repeatability and sensitivity to allow the differentiation between corrections with only three repetitions, and the duration of the psychophysical task (3 min for subject / condition / correction) makes it usable in the clinic.

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The work is a collaboration between the Institute of Optics and the spin-off of VioBio Lab 2Eyes Vision. MAS-2EV is a trademark of 2EyesVision.