Abstract

Multifocal contact lenses (MCLs) are one of the solutions to correct presbyopia, but their adoption is not widespread. To address this situation, visual simulators can be used to refine the adaptation process. This study aims to obtain accurate simulations for a visual simulator (SimVis Gekko; 2EyesVision) of daily soft MCL designs from four manufacturers. In-vitro characterization of these MCLs—several powers and additions- was obtained using NIMO TR-1504. From the averaged relative power profiles across powers, phase maps were reconstructed and the Through-Focus Visual Strehl metric was calculated for each MCL design. The SimVis Gekko simulation corresponding to each MCL design was obtained computationally and bench-validated. Finally, the MCL simulations were clinically validated involving presbyopic patients. The clinical validation results show a good agreement between the SimVis Gekko simulations and the real MCLs for through-focus visual acuity (TF-VA) curves and VA at three real distances. All MCL designs showed a partial correlation higher than 0.90 and a Root Mean Square Error below 0.07 logMAR between the TF-VA of simulations and Real MCLs across subjects. The validity of the simulation approach using SimVis Gekko and in-vitro measurements was confirmed in this study, opening the possibility to accelerate the adaptation of MCL

Citation

Abstract

Purpose

To propose new methods for eye selection in presbyopic monovision corrections.

Methods

Twenty subjects with presbyopia performed two standard methods of binary eye dominance identification (sensory with +1.50 diopters [D ]and +0.50 D and sighting with “hole-in-the-card”) and two psychophysical methods of perceived visual quality: (1) the Preferential test, 26 natural images were judged with the near addition in one eye or in the other in a 2-interval forced-choice task, and the Eye Dominance Strength (EDS) defined as the proportion of trials where one monovision is preferred over the other; (2) the Multifocal Acceptance Score (MAS-2EV) test, the perceived quality of a natural images set (for 2 luminance levels and distances) was scored and EDS defined as the score difference between monovision in one eye or the other. Left-eye and right-eye dominance are indicated with negative and positive values, respectively. Tests were performed using a Simultaneous Vision Simulator, which allows rapid changes between corrections.

Results

Standard sensory and sighting dominances matched in only 55% of subjects. The Preferential EDS (ranging from −0.7 to +0.9) and MAS-2EV EDS (ranging from −0.6 to +0.4) were highly correlated. Selecting the eye for far in monovision with the MAS-2EV, sensory, or sighting tests would have resulted in 79%, 64%, and 43% success considering the Preferential test as the gold standard.

Conclusions

Tests based on perceptual preference allow selection of the preferred monovision correction and measurement of dominance strength.

Translational Relevance

The binocular visual simulator allows efficient implementation of eye preference tests for monovision in clinical use.

Citation

Barcala, X., Zaytouny, A., Rego-Lorca, D., Sanchez-Quiros, J., Sanchez-Jean, R., Martinez-de-la-Casa, J. M., Dorronsoro, C., & Marcos, S.; Visual simulations of presbyopic corrections through cataract opacification. Journal of Cataract & Refractive Surgery 2022, 10: 1097. For more information, click here.

Abstract

Patients can rank the perceived image quality through cataract up to high level of opacity and that the preoperative ranking of the corrections matches that performed postoperatively through transparent media.

Purpose

To study the viability of visual simulation of presbyopic correction in patients with cataract and the effect and impact of the cataract on the perceived visual quality of the different simulated presbyopic corrections preoperatively and postoperatively.

Setting

San Carlos Clinical Hospital, Madrid, Spain.

Design

Observational, noninterventional, pilot study, early feasibility of the device being studied.

Methods

Cataract patients were tested preoperatively (n = 24) and postoperatively (n = 15) after bilateral implantation of monofocal intraocular lenses (IOLs). The degree of cataract was evaluated objectively with the objective scatter index (OSI). Visual acuity (VA) and perceived visual quality of natural scene images (Multifocal Acceptance Score) were measured before and after cataract surgery at far (4 m), intermediate (64 cm) and near distance (40 cm) with 4 binocular presbyopic corrections (single vision, bifocal, monovision and modified-monovision) simulated with a binocular Simultaneous Vision simulator based on temporal multiplexing.

Results

VA was significantly correlated with OSI (r = −0.71, P < .0005), although the visual degradation at far for each correction was constant and not correlated with OSI. The visual benefit at near distance provided by the presbyopic correction was noticeable (23.3% ± 27.6% across corrections) for OSI <5. The individual perceptual scores were highly correlated preoperatively vs postoperatively (r = 0.64, P < .0005) for all corrections and distances.

SimVis Gekko simulations vs clinical data in implanted patients

We incorporated real data from commercial lenses¹ obtained from literature in our visual simulator SimVis Gekko and measured defocus curves in presbyopic subjects. A very high correlation (>90%) was found between the curves of real patients implanted with the same lenses and the simulation.

ESCRS 2021 Talk

¹Sawides, Lucie, et al. “SimVis simulations of multifocal IOL designs based on public-literature data.” Optical Design and Engineering VIII. Vol. 11871. SPIE, 2021.

²Ribeiro, Filomena, and Tiago B. Ferreira. “Comparison of clinical outcomes of 3 trifocal IOLs.” Journal of Cataract & Refractive Surgery 46.9, 1247-1252 (2020).

³Gil, M.A., Varón, C., Cardona, G. et al. “Visual acuity and defocus curves with six multifocal intraocular lenses.” Int Ophthalmol 40, 393–401 (2020).

Citation

Sawides, L., de Castro, A., Lago, C. M., Barcala, X., Zaytouny, A., Marcos, S., & Dorronsoro, C.; SimVis simulations of multifocal IOL designs based on public-literature data. Optical Design and Engineering VIII (Vol. 11871, pp. 122-132). SPIE. (2021 Sept.). For more information, click here.

Abstract

As a large variety of intraocular lens (IOL) designs is commercially available in a growing market, selecting the best IOL for each patient has become a crucial task for a positive surgical outcome. Information about the measured or estimated performance of commercial lenses, as the through-focus modulation transfer function (TF-MTF) at a given frequency and pupil diameter, is routinely published. SimVis Gekko, a see-through simultaneous vision simulator based on temporal multiplexing, allows patients to experience the real world through different multifocal corrections prior to surgery. Implementing the maximum number of commercially available IOL designs into the portfolio of SimVis Gekko simulations is needed to provide a complete experience for the patients. We developed a new method to visually simulate IOL designs using temporal multiplexing, based only on publicly available information (mainly scientific literature or regulatory information), using the TF-MTF at 15cpd as input data to estimate the temporal coefficients that provide the best approximation to the real lens design. We validated the method with synthetic phase maps of equal area segmented bifocal and trifocal multifocal corrections for three pupil diameters of 3mm, 3.75mm and 4.5mm and applied it to three commercially available IOLs (trifocal or extended-depth-of-focus lenses). Through-focus visual acuity (TF-VA) curves were measured in seven patients using the SimVis simulations in the SimVis Gekko and matched, on average, the through-focus VA measurements in patients with implanted IOLs, reported in the scientific literature (on average logMAR RMS error=0.05, corresponding to less than 3 letters of visual acuity charts).

Keywords

Simultaneous vision; Temporal multiplexing; Visual simulations; MTF; Visual Strehl; Multifocal IOL designs; Through-focus optical quality

Computational, on-bench and clinical validations

The binocular defocus curve through SimVis Gekko simulating PresbyMAX Hybrid (by Schwind), extends the depth of focus by around 1.75D compared to the bilateral monofocal correction for far, maintaining a binocular VA above 0.2 LogMAR.

SimVis Gekko is a reliable visual simulator able to accurately simulate presbyopic corneal ablation patterns before surgery.

ESCRS 2022 E-Poster, PO465
Submission No:  FP-2534

¹Akondi, Vyas, et al. “Experimental validations of a tunable-lens-based visual demonstrator of multifocal corrections.” Biomedical Optics Express 9.12 (2018): 6302-6317

²Luger, Michiel HA, et al. “Presbyopic LASIK using hybrid bi-aspheric micro-monovision ablation profile for presbyopic corneal treatments.” American Journal of Ophthalmology 160.3 (2015): 493-505.