Reading ability and stereoacuity with combined implantation of refractive and diffractive multifocal intraocular lenses

Stereopsis Following Implantation of Presbyopia-Correcting Intraocular Lenses: A Narrative Review

Recent advancements in cataract surgery have broadened its scope from mere vision restoration to include correction of refractive errors and presbyopia. This evolution has introduced multifocal and extended depth-of-focus (EDOF) intraocular lenses (IOLs), allowing enhanced vision across multiple distances. However, the influence of these advanced IOLs on stereopsis remains controversial. Factors influencing stereopsis after surgery include visual acuity, interocular differences, residual astigmatism, and the type of IOL, etc. Binocular vision integration and neuroadaptation further affect stereopsis, especially in cases of presbyopia-correcting IOLs. It is widely acknowledged that bilateral implantation of presbyopia-correcting IOLs yield superior stereopsis compared to unilateral implantation. However, there remains no consensus on whether binocular implantation of multifocal or monofocal IOLs provides superior stereopsis. Most studies suggest no significant difference in stereopsis between these two types of implants. Among different types of multifocal IOLs, refractive multifocal IOLs may offer better stereopsis than diffractive multifocal IOLs when implanted bilaterally. Emerging EDOF and hybrid multifocal-EDOF IOLs also demonstrate promising postoperative stereopsis. Additionally, a mix-and-match strategy with different types of IOLs implanted in each eye may result in interocular differences in visual acuity at certain distances, potentially affecting stereopsis. Nevertheless, with appropriate selection, most patients can achieve satisfactory postoperative stereopsis. This review synthesizes current literature on the effects of presbyopia-correcting IOLs on postoperative stereopsis recovery following cataract surgery. Studies on stereopsis outcomes with different IOLs have yielded mixed results, urging further investigation for optimized surgical strategies and patient outcomes.

Stereoacuity and Aniseikonia: Evaluation Before and After Bilateral Implantation of Three Types of Presbyopia-Correcting Intraocular Lenses in Uncomplicated Phacoemulsification with Due Consideration of Interocular Differences in Higher Order Aberrations, Axial Lengths, Refractive Errors, and Acuities

Purpose

To determine if the changes in stereoacuity and aniseikonia, following bilateral implantation of presbyopia correcting intraocular lenses could be predicted from preoperative measurements of higher order aberrations (HOAs), axial lengths (AL), refractive errors (RE) and corrected visual acuities (CVAs).

Patients and Methods

Stereoacuity (Randot tests, @6m & 40cm, in steps of 20 arcsecs") vertical and horizontal aniseikonia (Awaya test @6m, in steps of 1%) with best correction and HOAs (Shack-Hartmann aberrometer) were measured before, 3 and 6 months after uncomplicated bilateral phacoemulsification. Twenty patients (I) underwent a mix-and-match procedure (Tecnis MF, ZKB00 in one eye and ZLB00 in the other), 17 (II) were implanted with a trifocal (AT LISA 839 triMP) and 18 (III) with a one-piece diffractive (Synergy OU) intraocular lens. The resultant aniseikonia (AR) of vertical and horizontal pairs of aniseikonia measurements was calculated using the Pythagorean theorem. Twenty untreated age/gender matched cases were recruited as controls (IV).

Results

The key results (p < 0.001) were a) stereoacuity at distance (SAD) and near (SAN) improved, AR reduced in groups I, II & III remaining unchanged in group IV; b) some significant intergroup differences in SAD, SAN & AR were detected at postop; c) at 6 months postop, changes (Δ=pre- minus postoperative value) correlated with preoperative values (x). Linear regression revealed, I ΔSAD=0.66x-57.47 [0.832, ±66.4], ΔSAN=0.96x-34.59 [0.821, ±16.9], ΔAR=0.93AR-2.12 [0.795, ±1.4] II ΔSAD=0.79x-62.91 [0.916, ±38.1], ΔSAN=0.96x-31.49 [0.892, ±8.0], ΔAR=0.91AR-0.91 [0.839, ±1.3] III ΔSAD=0.67x-35.50 [0.991, ±23.7], ΔSAN=0.88x-38.51[0.988, ±10.6], ΔAR=0.86AR-0.96 [0.900, ±1.3]. Figures in parentheses are the corresponding rs and ±limits of agreement between actual and estimated values. Definitive overarching associations connecting interocular differences in HOAs, AL, RE, and CVAs with SAD, SAN and AR were not found.

Conclusion

Changes in stereoacuity and aniseikonia can be predicted using preoperative values. ΔSAN can be predicted within ±1, and ΔAR within ±2, scale divisions. In group III ΔSAD can be predicted within ±1, and in group I ±3, scale divisions.

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.

Visual Results Following Implantation of a Refractive Multifocal Intraocular Lens in One Eye and a Diffractive in the Contralateral Eye

Objectives

To assess the visual outcomes in patients who underwent cataract surgery with multifocal intraocular lens (IOL) implantation using a “mix and match” approach.

Materials and Methods

Twenty patients (40 eyes) were involved in this prospective, nonrandomized study. Refractive multifocal IOLs (ReZoom NXG1) were implanted in patients’ dominant eyes and diffractive multifocal IOLs (Tecnis ZMA00) were implanted in their non-dominant eyes. Monocular and binocular uncorrected distance, intermediate and near visual acuity (logMAR), and contrast sensitivity levels were measured at 1, 3, and 6 months after cataract surgery. Defocus curves, reading speeds, patient satisfaction, spectacle dependence, and halo and glare symptoms were also evaluated at 6 months after the surgery. Postoperative quality of life was assessed with the Turkish version of National Eye Institute Visual Function Questionnaire-25.

Results

The study group comprised 8 females and 12 males with a mean age of 69.45±10.76 years (range, 31-86 years). The uncorrected distance and intermediate visual acuity levels were significantly better in the ReZoom-implanted eyes at postoperative 6 months (p=0.026 and p=0.037, respectively). There was no statistically significant difference in uncorrected near visual acuity (p>0.05). There was no statistically significant difference in contrast sensitivity, reading speed, halos, or glare between the groups (p<0.05). Mild glare/halo was reported by 40% of the subjects. The mean patient satisfaction was 95% and all patients were spectacle independent.

Conclusion

Mixing and matching multifocal IOLs in selected cataract patients provides excellent visual outcome, a high level of patient satisfaction, and spectacle independency.

Short-term outcomes of combined implantation of diffractive multifocal intraocular lenses with different addition power

PURPOSE

To compare short-term binocular visual function between patients implanted with diffractive multifocal intraocular lenses (MIOLs) of different near addition powers in each eye or the same MIOLs bilaterally.

METHODS

Seventy patients scheduled for implantation of diffractive MIOLs were divided into two groups: (i) mix and match group, a MIOL with +3.0 dioptre (D) addition power implanted in the dominant eye (Alcon SN60D1) and a MIOL with +4.0D power implanted in the non-dominant eye (SN60D3) or (ii) same MIOL group, same MIOL (SN60D1) implanted bilaterally. At 3 months postoperatively, we examined binocular visual acuity (VA) at various distances, binocular contrast VA and that with a glare (glare VA), and near stereoacuity.

RESULTS

Mean binocular uncorrected (UNVA) or corrected near VA (CNVA) at 0.3 m was significantly better in the mix and match group than in the same MIOL group (p ≤ 0.0066). Binocular uncorrected and distance-corrected VA at other distances was similar. Binocular UNVA of 0.8 or better was achieved in 77.1% of patients in the mix and match group and 45.7% in the same MIOL group (p = 0.0144). Binocular contrast and glare VA, and stereoacuity did not significantly differ between groups. Spectacle independence and patient satisfaction with near vision were significantly better in the mix and match group (p ≤ 0.0195).

CONCLUSION

Mix and match implantation of diffractive MIOLs with different addition power provides a better binocular VA curve and spectacle independence than bilateral implantation of the same MIOLs, without compromising contrast sensitivity and stereopsis.

Cost-effectiveness comparison between monofocal and multifocal intraocular lens implantation for cataract patients in Taiwan

PURPOSE

Our aim was to conduct a cost-effectiveness analysis (CEA) of monofocal and multifocal intraocular lenses (IOLs) for cataract patients in Taiwan.

METHODS

This prospective nonrandomized study was designed to evaluate the effectiveness of monofocal and multifocal IOLs by means of visual performance, visual quality, vision-related quality of life, and spectacle-independence rates. The direct costs were calculated using the payment points of the fee schedule for medical services multiplied by the treatment items. The concept of incremental cost effectiveness ratios was used to evaluate the costs of different types of IOLs in cataract surgery and postoperative outcomes in patients.

FINDINGS

A total of 61 patients from the monofocal IOL group (n = 21), multifocal IOL group 1 (n = 22), and multifocal IOL group 2 (n = 18) who completed the study were included in the analysis. No significant differences were observed in mean ages or patient to eye ratio. Significant differences in effectiveness after the implantations of monofocal and multifocal IOLs were observed for spectacle-free rate and monocular contrast sensitivity under glare conditions only. The incremental cost-effectiveness ratios of monofocal versus multifocal IOLs indicated that it cost an additional $57 to $58 (US dollars) to increase each 1% of the spectacle-independence rate.

IMPLICATIONS

This study's results indicated that multifocal IOLs provided better effectiveness on vision-related indicators like the incremental cost effectiveness ratios of postoperative spectacle-independence rate and binocular best-corrected visual acuity measurements at near vision. Our findings suggest that multifocal IOLs can be highly cost effective for patients who prefer to be spectacle free, so it is important to ensure that patients have realistic expectations when making choices between monofocal and multifocal IOLs.

Comparison of Visual Performance after Implantation of 3 Types of Intraocular Lenses: Accommodative, Multifocal, and Monofocal

Purpose

To compare the performance of accommodative, multifocal, and monofocal intraocular lenses (IOLs).

Methods

In this clinical control study, 3 types of IOL were implanted in 128 eyes of 86 patients with age-related cataract who underwent phacoemulsification. Accommodative (Tetraflex), multifocal (ZMA00), and monofocal (Akreos Advanced Optics [AO]) IOLs were implanted into 43, 40, and 45 eyes, respectively. The uncorrected, best-corrected distance, contrast sensitivity, and distance-corrected intermediate and near visual acuity (UCDVA, BCDVA, CSVA, DCIVA, and DCNVA, respectively), amplitude of pseudoaccommodation, and patient satisfaction were measured at 1, 3, and 12 months after surgery.

Results

Differences in CSVA at all contrast degrees, UCDVA, and BCDVA among the 3 groups were not significant. Patients in the Akreos AO group exhibited a poorer DCIVA and DCNVA and experienced less pseudoaccommodation compared to patients in the other 2 groups at 3 and 12 months after surgery (p<0.01). Patients in the ZMA00 group exhibited a better DCIVA and experienced more pseudoaccommodation than patients in the Tetraflex group (3 months: p<0.05, 12 months: p<0.01 for both outcomes). Three months after surgery, total spectacle independence was achieved by 84.4%, 60.7%, and 17.2% of the ZMA00, Tetraflex, and Akreos AO group patients, respectively.

Conclusions

All 3 types of IOLs allowed greater distance visual acuity; however, multifocal IOLs produced better DCIVA and DCNVA and more pseudoaccommodation and spectacle independence. Accommodative IOLs ranked second. Neither accommodative nor multifocal IOLs reduced CSVA.

Visual function through 4 contact lens-based pinhole systems for presbyopia

PURPOSE

To evaluate the effects of different contact lens-based artificial pupil designs on visual performance.

SETTING

University of Valencia, Burjassot, Spain, and University of Manchester, Manchester, United Kingdom.

DESIGN

Comparative case series.

METHODS

Presbyopic patients were evaluated using 4 artificial pupil designs in the nondominant eye. Binocular uncorrected distance visual acuity (UDVA), binocular corrected distance visual acuity (CDVA), binocular uncorrected near visual acuity (UNVA), binocular distance-corrected near visual acuity (DCNVA), defocus curve, binocular distance, and near contrast sensitivity under photopic and mesopic conditions, and stereoacuity were measured after contact lens fitting.

RESULTS

The mean UDVA and CDVA ranged from 0.04 ± 0.05 (SD) to -0.01 ± 0.04 logMAR and from -0.02 ± 0.05 to -0.05 ± 0.03 logMAR, respectively. The UNVA and DCNVA ranged from 0.37 ± 0.11 to 0.42 ± 0.20 logMAR and from 0.35 ± 0.17 to 0.38 ± 0.12 logMAR, respectively. The difference in binocular distance contrast sensitivity was statistically significant between the pinhole systems and the control group (distance-corrected patients without pinhole lens) for 6 cycles per degree (cpd), 12 cpd, and 18 cpd; for near vision, differences were also significant for 3 cpd at the 2 luminance levels (P<.05). Stereoacuity values for near vision were not significantly different between the 4 pinhole systems (P>.05).

CONCLUSIONS

Soft contact lens apertures provide good visual acuity at distance, functional intermediate vision, and poor near visual acuity and stereoacuity. An improvement in visual performance with decreasing pupil diameter was not found.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Clinical evaluation of two multifocal intraocular lens implantation patterns

AIM

To evaluate the visual outcomes and patient satisfaction of two multifocal intraocular lens implantation patterns, with the decision between the two patterns being guided by the patients' choice of visual zones that best suited their lifestyle, or lifestyle zones.

METHODS

This is a prospective non-randomized comparative study. The lifestyle zones of 32 consecutive age-related cataract patients (64 eyes) were investigated individually to guide the surgical decision between two multifocal intraocular lens implantation patterns. The first group (MIX) received a combined implantation of a ReZoom NXG1 lens in the dominant eye and a Tecnis ZM900 lens in the other eye. The second group (MATCH) received bilateral ReZoom NXG1 lenses. One year postoperatively, the patients were assessed for binocular uncorrected visual acuity, reading visual acuity, reading speed and depth of focus under different luminance and were surveyed for visual disturbances, satisfaction and complete spectacle independence.

RESULTS

According to the determination of lifestyle zones, 18 and 14 patients were included in the MIX and MATCH groups, respectively. One year postoperatively, each of the patients exhibited positive visual outcomes and lifestyle satisfaction, although there were still some differences between the two groups. Generally, patients in the MATCH group had better distance visual acuity than those in the MIX group. In contrast, patients in the MIX group had better near visual acuity, better reading acuity and better reading speed than those in the MATCH group. Between the two groups, there was no clear difference in intermediate visual acuity, and the depths of focus between the two groups were approximately equal. The results of the mean NEI-RQL-42 questionnaire score, overall satisfaction, and complete spectacle independence did not differ between the two groups.

CONCLUSION

Different multifocal intraocular lenses implantation patterns can have differing advantages and disadvantages; however, the best results with respect to visual outcome and patient satisfaction can be achieved by taking individual lifestyle zones into account.