Visual and optical performance with hybrid multifocal intraocular lenses

Stereoacuity and Multifocal Intraocular Lenses - a Systematic Review

Background

Among various visual functions, stereoacuity, or the ability to perceive depth, is the most sophisticated binocular function. Many publications discuss the influence of retinal image formation by multifocal intraocular lenses on glare and contrast sensitivity, but only a few present results of testing binocular vision in patients with multifocal intraocular lenses.

Objective

This article is designed to review the results of testing binocular vision in patients with multifocal intraocular lenses implanted in cataract surgery.

Methods

This article was performed based on a literature review and Internet search through scientific databases such as PubMed, Scopus, Web of Science, and Google Scholar.

Results

Some reports found that patients implanted with the monofocal lens, when measured with a near addition, presented statistically significant better stereoacuity scores than those implanted with any of the multifocal intraocular lens types. When the TNO test was used for measurement, statistically significant better stereoacuity was disclosed with the refractive multifocal intraocular lens than with the diffractive-based multifocal intraocular lens design. Stereoacuity scores, even within the same types of lenses, were significantly better with the Titmus test than with the TNO test.

Conclusion

Stereoacuity is not affected by multifocality-induced retinal blur as it is by other causes of image degradation such as small residual refractive error very early opacification of ocular media or dry eye. Multifocal intraocular lenses do not cause more functional aniseikonia than would be expected with a monofocal intraocular lens. Since stereoacuity is compromised with unilateral multifocal intraocular lens implantation bilateral implantation should be attempted.

Characterization of diffractive bifocal intraocular lenses

Multifocal intraocular lenses incorporate a variety of design considerations, including dimensioning of the base monofocal shape and the diffraction grating. While studying three different lens models, we present a practical approach for mathematical modelling and evaluation of these geometries. Contrary to typical lens measurement methods, non-contact measurements were performed on the Alcon SN6AD1, HumanOptics MS 612 DAY and the AMO ZMA00 lenses using a confocal microscope. Subsequent data processing includes centering, tilting correction, filtering and an algorithmic decomposition into a conic and polynomial part and the diffraction grating. Lastly, evaluation of fitting parameters and grating shape is done to allow for inferences about further optical properties. Results and analysis show the confocal microscope to be a suitable imaging method for lens measurements. The processing of this data enables the reconstruction of the annular diffraction grating over the complete lens diameter. Apodization, near addition and diffraction efficiency characteristics are found utilizing the grating shape. Additionally, near-optical axis curvature, asphericity and higher order polynomials are identified qualitatively from the reconstruction of the monofocal base form. Derived properties also include the lens optical base and addition power. By making use of the surface geometries, as well as the lens' material and thickness, a full lens model can be created for further studies. In summary, our analytical approach enables the insight to various intraocular lens design decisions. Furthermore, this procedure is suitable for lens model creation for research and simulation.

Optical and Clinical Outcomes of an Extended Range of Vision Intraocular Lens

PURPOSE

To assess the in vitro optical quality and halo formation of the AcrySof IQ Vivity intraocular lens (IOL) (Alcon Laboratories, Inc) and to evaluate the clinical outcomes in patients who had bilateral implantation of this IOL.

METHODS

The optical quality was evaluated with the PMTF optical bench (Lambda-X). Through-focus modulation transfer function area (MTFa) curves between -5.00 and +2.00 diopters (D) were obtained for 3- and 4.5-mm pupil apertures. The halo was assessed in vitro with a test bench. The clinical study included 30 patients. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and binocular defocus curve were evaluated 6 months postoperatively.

RESULTS

The through-focus MTFa curve for the 4.5-mm pupil size showed only one peak at distance focus (38.4 units). For the 3-mm pupil size, the through-focus MTFa showed a lower peak of MTFa (28.9 units), located at -0.70 D, and an extended depth of focus up to -2.20 D. The halo formed was larger and more intense compared to a standard monofocal IOL. The clinical outcomes at 6 months revealed satisfactory visual acuity outcomes. All patients achieved a binocular CDVA of 0.1 logMAR or better. The mean visual acuity was better than 0.2 logMAR between +1.00 and -2.00 D of defocus. At a vergence of -2.50 D, the visual acuity was 0.31 ± 0.09 logMAR.

CONCLUSIONS

The AcrySof IQ Vivity IOL provided good distance optical and visual quality and an extended range of focus of approximately 2.00 D, obtaining an optimal or functional visual acuity up to 50 to 40 cm. The halo formed was low intensity overall, but higher intensity than a monofocal IOL. [J Refract Surg. 2022;38(3):168-176.].

Visual performance of four types of diffractive multifocal intraocular lenses and a review of articles

AIM

To compare the clinical outcomes of a variety of multifocal intraocular lenses (MIOLs) in patients diagnosed with presbyopia or cataracts.

METHODS

This clinical trial study included 141 patients (282 eyes) with different MIOLs implantation. The Symfony (60 eyes), the ReSTOR (100 eyes), the AT LISAtri (60 eyes), and the PanOptix (62 eyes) intraocular lenses were evaluated in this prospective interventional study. The near, intermediate, and distant visual acuities, contrast sensitivity, and defocus curve were measured as valid criteria. To statistically analyze the results, we used the Statistical Package for Social Science software, the non-parametric Wilcoxon signed-rank t, the one-way analysis of variance and the Tukey's post-hoc test in our analysis. Moreover, we conducted a detailed literature search on the PubMed database in English about MIOLs, in total 59 studies were included in this review article.

RESULTS

The four approaches did not show any significant difference in the best-corrected distance visual acuity (P>0.05). The defocus curves at the contrast of 100% showed that trifocal IOLs had better intermediate performance than the bifocal IOL (P<0.05). There were no statistically significant differences between AT LISAtri and PanOptix lenses for visual acuity at all distances. The eyes with PanOptix, Symfony, and AT LISAtri IOL showed better contrast sensitivity than those ReSTOR at spatial frequencies of 1, 3, and 6 cpd in photopic and mesopic conditions (P<0.001).

CONCLUSION

All four groups of the multifocal lenses were satisfying in terms of distance and near vision. Also, the group of trifocal lenses led to satisfactory outcomes in intermediate vision, without degradation in quality of vision.

Optical and visual quality assessment of an extended depth-of-focus intraocular lens based on spherical aberration of different sign

PURPOSE

To assess the optical quality and the visual performance of patients implanted with an extended depth-of-focus (EDOF) intraocular lens (IOL).

METHODS

Thirty-eight eyes underwent implantation of the Mini WELL Ready EDOF IOL and were evaluated at 3-months postsurgery. Higher-order aberrations (HOAs) and modular transfer function (MTF) were measured at 3- and 5-mm pupils. Binocular uncorrected-distance visual acuity (UDVA) and corrected-distance visual acuity (CDVA), uncorrected-distance intermediate visual acuity (UIVA) and corrected-distance intermediate visual acuity (CDIVA) at 80 cm, and uncorrected-distance near visual acuity (UNVA) and corrected-distance near visual acuity (CDNVA) at 40 cm were obtained. Postoperative refraction, binocular defocus curve, halometry and subjective ad hoc patients' questionnaire were also evaluated.

RESULTS

HOAs were 0.171 ± 0.046 µm and 0.406 ± 0.137 µm at 3 and 5 mm, respectively. MTFs decreased as the spatial frequency increased being comparable for both pupils. 92.10% of eyes were within ± 1.00D, and the mean postoperative spherical equivalent was - 0.25 ± 0.65D. Mean UDVA, UIVA and UNVA were 0.06 ± 0.12, 0.05 ± 0.10 and 0.26 ± 0.28 logMAR, respectively. Mean CDVA, CDIVA and CDNVA were - 0.01 ± 0.08, 0.06 ± 0.11 and 0.24 ± 0.12 logMAR, respectively. Defocus curve showed a continuous range of vision, especially at intermediate distances. Mean discrimination index was 0.79 ± 0.04. Questionnaire revealed that about 79% of patients reported a high or moderately high satisfaction with the procedure, and about 95% of patients would undergo the same procedure again.

CONCLUSIONS

The Mini WELL Ready EDOF IOL provided good optical and visual quality with high level of patient satisfaction and seems to be a valuable option to provide unaided vision at different distances minimizing visual disturbances.

Comparison of Post-Cataract Surgery Visual Outcomes and Quality of Life in Patients Bilaterally Implanted with Multifocal Intraocular Lenses

Introduction

The present study compared visual outcomes in eyes with bilateral implantation of two multifocal intraocular lenses (MFIOLs)—the Eyecryl™ ACTV diffractive multifocal IOL (group 1) and AcrySof^® IQ ReSTOR^® multifocal IOL (group 2).

Methods

This was a prospective, two-group observational longitudinal study of 118 eyes from 59 patients conducted at Laxmi Eye Institute, Panvel, India. We evaluated the patients at 1, 3, and 6 months. We assessed visual acuity, contrast sensitivity, higher-order aberrations, reading speed, defocus curve, stereopsis, quality of life (QOL), and adverse events in these participants.

Results

The median (interquartile range) best-corrected distance visual acuity was 0.18 (0, 0.18) in group 1 and 0.18 (0, 0.18) in group 2 at 1, 3, and 6 months; the difference was not statistically significant (p = 0.48). The binocular defocus curve in both groups showed two peaks at 0.0 to −0.5 D and at −2.5 D. The mean (95% confidence interval) critical print size was significantly different between groups 1 and 2 at low illumination (0.918 [0.905, 0.931] vs 1.154 [1.128, 1.180]; p = 0.004). Contrast sensitivity was significantly better in group 1 under mesopic conditions but not under scotopic conditions. Though total QOL did not differ significantly between groups, the psychosocial quality of life was significantly better in group 1. About 23% of patients in group 2 reported unwanted images, compared with 0% in group 1 (p = 0.01).

Conclusion

We found that the Eyecryl and AcrySof groups were comparable for best-corrected visual acuity, photopic contrast sensitivity, defocus curve, reading parameters, stereopsis, and quality of vision. However, the Eyecryl group had better mesopic contrast and a lower proportion of unwanted images. Psychosocial quality of life was significantly better in the Eyecryl group; however, satisfaction was similar between groups. The cost of one of the lenses is less than the other. Thus, individuals with limited resources may opt for the Eyecryl™ ACTV, with similar visual outcomes.

Comparison of visual quality and subjective outcomes among 3 trifocal intraocular lenses and 1 bifocal intraocular lens

PURPOSE

To compare visual quality and subjective outcomes between 3 trifocal intraocular lenses (IOLs) and 1 bifocal IOL.

SETTING

Clínica Oftalmológica Martínez de Carneros, Madrid, Spain.

DESIGN

Prospective case series.

METHODS

This study comprised patients having bilateral phacoemulsification and implantation of an AcrySof IQ PanOptix, AT LISA tri 839MP, FineVision, or Tecnis ZLB00 IOL. Postoperative evaluation included logarithm of the minimum angle of resolution (logMAR) uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and distance-corrected near visual acuity (DCNVA); reading speed; through-focus logMAR visual acuity at 100%, 50%, and 12% contrast; and contrast sensitivity function (CSF) under photopic and mesopic conditions. Subjective outcomes were assessed using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25).

RESULTS

The study enrolled 160 patients, 40 in each group. Six months postoperatively, there were no statistically significant between-group differences in the spherical equivalent, UDVA, CDVA, DCNVA, reading performance, or CSF under photopic and mesopic conditions. The defocus curves at 100%, 50%, and 15% of contrast showed that trifocal IOLs, especially the AcrySof PanOptix, had better intermediate performance than the bifocal IOL and comparable outcomes at far and near distances. There were no statistically significant differences in the postoperative NEI VFQ-25 questionnaire scores between the 4 IOL groups.

CONCLUSION

The trifocal IOLs provided better intermediate distance vision than the bifocal IOL without compromising distance or near vision.

Stereo-acuity in patients implanted with multifocal intraocular lenses: is the choice of stereotest relevant?

PURPOSE

A randomized and double-blinded study design was implemented to assess the stereo-acuity in patients symmetrically implanted with four types of multifocal intraocular lenses (MIOLs), compared to a monofocal lens (control group). In addition, the influence of the type of test employed for the evaluation of stereo-acuity was explored.

MATERIALS AND METHODS

Six months after cataract intervention, stereo-acuity was measured with the Titmus and TNO stereotests in 143 patients implanted with one of the following MIOL lens types: hybrid spherical SN60D3, hybrid aspheric SN6AD1, diffractive aspheric ZMA00 and refractive spherical NXG1. A control group implanted with the monofocal aspheric ZA9003 (in which stereo-acuity was measured with a near addition) was also included in the study.

RESULTS

Statistically significant better stereo-acuity was found in the monofocal group with both stereotests (except for the SN60D3 group with the Titmus test) (all p < 0.001). No significant differences in stereo-acuity between MIOLs were found using the Titmus test. However, with the TNO, patients implanted with hybrid diffractive MIOLs exhibited statistically significant worse stereo-acuity than those with the refractive design (SN60D3, p < 0.001; SN6AD1, p = 0.006).

CONCLUSIONS

Patients implanted with MIOLs have worse stereo-acuity than those implanted with monofocal IOLs due to the decrease in retinal image contrast originating in the simultaneous presence of two images. A wavelength-based stereotest such as the TNO induces large differences in image contrast between fellow eyes implanted with diffractive-based MIOLs, which may result in an underestimation of the real stereo-acuity of the patient.

Visual performance of a multifocal toric soft contact lens

PURPOSE

To evaluate the visual performance of the Proclear multifocal toric contact lens (CL; CooperVision, US) for both presbyopia and astigmatism correction.

METHODS

In this crossover study design, 20 presbyopic subjects with astigmatism were fitted in a random order with either Proclear multifocal toric CL or Proclear toric single vision distance CL (DCL) combined with reading spectacles. After 1 month, high-contrast distance visual acuity, near high-contrast visual acuity, distance contrast sensitivity (CS) under photopic and mesopic conditions without and with glare, near CS, defocus curve, and stereopsis were measured. Subjects were then refitted with the alternative correction, and the procedure was repeated.

RESULTS

Repeated measures analysis of variance revealed differences in visual acuity and CS (p < 0.001) between groups. Mean binocular distance visual acuity and near visual acuity obtained with multifocal toric CL were -0.01 ± 0.03 logMAR and -0.04 ± 0.06 logMAR, respectively. The mean distance CS with the multifocal toric CL was within normal limits under photopic and mesopic conditions. Under photopic conditions, distant CS was better with distance CL than with multifocal toric CL only at 18 cycles/degree. Under mesopic conditions without and with glare, there were differences between both CLs in distant CS for all spatial frequencies. There were differences between the two CLs in near CS for all spatial frequencies. Mean values of stereopsis obtained with multifocal toric CLs and with the DCL combined with reading glasses were 62 ± 12 sec of arc and 59 ± 12 sec of arc, respectively (p = 0.06). Near range of clear vision with the multifocal toric CLs was 1.55 ± 0.33D.

CONCLUSIONS

The results of this study suggest that the multifocal toric CL studied is a good option to compensate both presbyopia and astigmatism, providing an optimal distance and near visual quality without compromising the stereopsis.

Effect of multizone refractive multifocal contact lenses on standard automated perimetry

PURPOSE

The aim of this study was to evaluate whether the creation of 2 foci (distance and near) provided by multizone refractive multifocal contact lenses (CLs) for presbyopia correction affects the measurements on Humphreys 24-2 Swedish interactive threshold algorithm (SITA) standard automated perimetry (SAP).

METHODS

In this crossover study, 30 subjects were fitted in random order with either a multifocal CL or a monofocal CL. After 1 month, a Humphrey 24-2 SITA standard strategy was performed. The visual field global indices (the mean deviation [MD] and pattern standard deviation [PSD]), reliability indices, test duration, and number of depressed points deviating at P<5%, P<2%, P<1%, and P<0.5% on pattern deviation probability plots were determined and compared between multifocal and monofocal CLs.

RESULTS

Thirty eyes of 30 subjects were included in this study. There were no statistically significant differences in reliability indices or test duration. There was a statistically significant reduction in the MD with the multifocal CL compared with monfocal CL (P=0.001). Differences were not found in PSD nor in the number of depressed points deviating at P<5%, P<2%, P<1%, and P<0.5% in the pattern deviation probability maps studied.

CONCLUSIONS

The results of this study suggest that the multizone refractive lens produces a generalized depression in threshold sensitivity as measured by the Humphreys 24-2 SITA SAP.