Temporal multiplexing to simulate multifocal intraocular lenses: theoretical considerations

Abstract

Fast tunable lenses allow an effective design of a portable simultaneous vision simulator (SimVis) of multifocal corrections. A novel method of evaluating the temporal profile of a tunable lens in simulating different multifocal intraocular lenses (M-IOLs) is presented. The proposed method involves the characteristic fitting of the through-focus (TF) optical quality of the multifocal component of a given M-IOL to a linear combination of TF optical quality of monofocal lenses viable with a tunable lens. Three different types of M-IOL designs are tested, namely: segmented refractive, diffractive and refractive extended depth of focus. The metric used for the optical evaluation of the temporal profile is the visual Strehl (VS) ratio. It is shown that the time profiles generated with the VS ratio as a metric in SimVis resulted in TF VS ratio and TF simulated images that closely matched the TF VS ratio and TF simulated images predicted with the M-IOL. The effects of temporal sampling, varying pupil size, monochromatic aberrations, longitudinal chromatic aberrations and temporal dynamics on SimVis are discussed.

Experimental validations of a tunable-lens-based visual demonstrator of multifocal corrections

“…Here, three different multifocal intraocular lens designs are testeddiffractive trifocal (D-T), refractive segmented bifocal (R-SB), and refractive EDOF (R-EDOF). Section 2.1 briefly introduces the metric-based evaluation of the theoretical SimVis temporal profile presented in [15] and points out the drawbacks of the non-iterative regression. Section 2.2 describes the temporal sampling constraints.…”

“…A prerequisite to demonstrate any given multifocal design with SimVis is the determination of the corresponding amount of time to be spent by the tunable lens in each focusing distance (equivalently, the theoretical SimVis temporal profile). This is possible with the help of a metric-based evaluation [15]. The calculation uses the through-focus (TF) Visual Strehl (VS) ratio of a given multifocal phase map.…”

“…Alternately, the multifocal phase maps corresponding to the contact lenses can be evaluated from the optical power profiles [17]. In our earlier study [15], the time coefficients were obtained by fitting the TF VS ratio of the multifocal phase pattern with TF VS ratios of all possible monofocal lenses feasible with the tunable lens at any given instance [18]. We used a non-iterative least square fitting approach [15].…”

“…In our earlier study [15], the time coefficients were obtained by fitting the TF VS ratio of the multifocal phase pattern with TF VS ratios of all possible monofocal lenses feasible with the tunable lens at any given instance [18]. We used a non-iterative least square fitting approach [15]. While it produced an accurate representation of the IOL, the undersampling procedure and optimal temporal sampling had to be adjusted to each multifocal design.…”

VioBio lab adaptive optics: technology and applications by women vision scientists

“…This phase map is subsequently mapped in the AO mirror or the SLM, considering the working principle of the lens (refractive or diffractive) and the presence of smooth or abrupt surfaces. The phase map representing an IOL ( Figure ) is obtained by subtracting the simulated wavefront map from an eye model implanted with the IOL from that of the phakic eye, using virtual ray tracing (in OpticStudio, http://www.zemax.com/products/opticstudio). The phakic eye is designed as “neutral” with the same parameters as a pseudophakic model eye (cornea, axial length, etc.)…”