Visual Performance After Contralateral Implantation of Multifocal Intraocular Lenses With +3.0 and +4.0 Diopter Additions

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1 ORIGINAL CLINICAL STUDY Visual Performance After Contralateral Implantation of Multifocal Intraocular Lenses With +3.0 and +4.0 Diopter Additions Kunihiko Nakamura, MD, PhD, Hiroko Bissen-Miyajima, MD, PhD, Mami Yoshino, MD, and Shinichi Oki Purpose: To evaluate visual performance after contralateral implantation of AcrySof ReSTOR aspheric intraocular lenses (IOLs) with +3.0 and +4.0 diopter near additions. Design: This was a retrospective case study conducted at Tokyo Dental College Suidobashi Hospital in Tokyo, Japan. Methods: Eleven patients who were implanted with the SN6AD1 IOL and the SN6AD3 IOL contralaterally were included in this study. The distance, intermediate (1 m, 50 cm), and near (40 and 30 cm) uncorrected and corrected binocular visual acuity (VA), contrast sensitivity, depth of focus, and patient satisfaction were assessed more than 1 month postoperatively. Results: Postoperatively, the mean uncorrected (corrected) binocular logarithm of the minimum angle of resolution VA levels were as follows: distance, j0.120 (j0.163); intermediate, 1 m, (0.012) and 50 cm, (0.006); and near, 40 cm, (j0.040) and 30 cm, (j0.053). The depth of focus had a smooth curve with double peaks. The mean contrast sensitivity was normal at all spatial frequencies. All patients were spectacle independent and expressed high satisfaction. Conclusions: Contralateral implantation of multifocal IOLs with +3.0 and +4.0 D additions takes advantage of the good uncorrected near VA provided by both IOLs and may be an option for patients who require a broader range of good uncorrected near VA. Key Words: multifocal IOL, near additional power, uncorrected visual acuity (Asia Pac J Ophthalmol 2015;4: 329Y333) New-generation multifocal intraocular lenses (IOLs) have been designed to provide distance and near visual acuities (VAs) to increase spectacle independence, and patients have reported good visual function. 1Y5 The addition power for near focus is +4.0 diopters (D) and the theoretical distance is 30 cm. Two drawbacks of this addition power are that the focal point is too close for computer work and there is an extreme decrease in intermediate vision. To compensate, an apodized diffractive multifocal IOL (AcrySof IQ ReSTOR SN6AD1, Alcon) with a lower addition power, +3.0 D addition, was developed. Patients expressed satisfaction with the extended reading distance compared with previously approved apodized diffractive multifocal IOLs with a +4.0 D addition. 6Y9 However, Kohnen et al 7 From the Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan. Received for publication December 11, 2014; accepted July 20, H.B.M. and K.N. have received lecture fees from Alcon. The authors have no conflicts of interest to declare. Reprints: Kunihiko Nakamura, MD, PhD, Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Misaki-cho, Chiyoda-ku, Tokyo , Japan. up4k-nkmr@asahi-net.or.jp. Copyright * 2015 by Asia Pacific Academy of Ophthalmology. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. ISSN: DOI: /APO reported that 9% of patients used near spectacles after bilateral implantation of the SN6AD1 IOL, and Petermeier et al 9 reported that 8% of patients used near spectacles after bilateral implantation of the SN6AD1 IOL in contrast to no need for near spectacles after bilateral implantation of the SN6AD3 IOL. In a clinical study of the SN6AD1 IOL in Japanese patients, 17.5% used spectacles for near vision. 10 Most patients were spectacle independent after bilateral implantation of a multifocal IOL with a +3.0 D addition, but the rate of spectacle dependence for near vision increased compared with the previous results with a multifocal IOL with a +4.0 D addition. Bilateral implantation of a multifocal IOL with a +4.0 D addition may be advantageous in reducing the need to use spectacles for reading. Currently, several methods of combined multifocal IOL implantation have been suggested to meet the diverse demands of patients. Combining a refractive IOL and diffractive IOL, 11Y13 a monofocal IOL and multifocal IOL, 14 or an accommodative IOL and multifocal IOL 15 has been suggested; combining multifocal IOLs with different addition powers may be another option. 16 The purposes of this retrospective study were to evaluate visual performance after contralateral implantation of apodized diffractive aspheric multifocal IOLs with +3.0 and +4.0 D addition powers and to assess whether this combination is advantageous for patients who want near focus between 30 and 40 cm. MATERIALS AND METHODS This retrospective study included 22 eyes of 11 patients (mean age, 60.8 T 5.7 years) who underwent cataract surgery with contralateral implantation of apodized diffractive aspheric multifocal IOLs with +3.0 and +4.0 D addition powers at Tokyo Dental College Suidobashi Hospital to satisfy the patients preferences for near focus. Patients with corneal astigmatism over 1.5 D and any history of ocular pathology except cataract were excluded. This study adhered to the tenets of the Declaration of Helsinki; all patients provided informed consent. The demographic and preoperative patient characteristics are shown in Table 1. The implanted IOLs were the AcrySof IQ ReSTOR +3.0 D (SN6AD1) and AcrySof IQ ReSTOR +4.0 D (SN6AD3). Both IOLs have a single-piece design with an apodized diffractive multifocal optic that occupies the central 3.6-mm region. Apodization is a gradual decrease in diffractive step heights from the optical center to periphery, which avoids reduction of nighttime contrast sensitivity. The anterior surface is aspheric to reduce postoperative ocular spherical aberrations. A multifocal IOL with +3.0 D addition corresponds to +2.5 D at the spectacle plane, and a multifocal IOL with +4.0 D addition corresponds to +3.2 D and has narrower defocus profile peaks. The inferior eye with corrected visual acuity (VA) was selected for the first surgery, and a dominant eye test was not performed. The multifocal IOL for the first eye was selected depending on the patient s lifestyle, for example, a multifocal Asia-Pacific Journal of Ophthalmology & Volume 4, Number 6, November/December

2 Nakamura et al Asia-Pacific Journal of Ophthalmology & Volume 4, Number 6, November/December 2015 TABLE 1. Demographic Data and Preoperative Characteristics of Patients Parameter No. eyes/patients 22/11 Men/women 5/6 Mean age, years (SD) 60.5 (12.5) Range, 32Y77 Mean corneal astigmatism, D (SD) 0.75 (0.42) Range, 0.22Y1.21 Mean spherical equivalent (SD) 0.35 (2.11) Range, 5.5Y3.0 Mean axial length, mm (SD) (0.81) Range, 21.49Y24.54 IOL with a +3.0 D addition was selected if the patient primarily performed computer work. However, if the patient read at 30 cm, a multifocal IOL with a +4.0 D addition was selected. After the first surgery, when some patients expressed dissatisfaction with deskwork or reading at near, implantation of a multifocal IOL with a different addition power was considered. If the patient was implanted with a multifocal IOL with a +3.0 D addition and wanted a closer focal point, a multifocal IOL with a +4.0 D addition was implanted in the fellow eye, and if the patient was implanted with a multifocal IOL with a +4.0 D addition and reported difficulty with computer work, a multifocal IOL with a +3.0 D addition was implanted in the fellow eye. The IOL power was determined based on the axial length and corneal refraction measured using the IOLMaster (Carl Zeiss Meditec) and the SRK/T formula. Emmetropia was targeted in all patients. One surgeon (H.B.M.) performed all the surgeries. Under topical anesthesia, a clear corneal temporal incision and continuous curvilinear capsulorhexis with a 5.0- to 5.5-mm diameter were created. After extraction of the crystalline lens during phacoemulsification, the IOL was implanted in the capsular bag using an injector. No intraoperative complications developed. Postoperative anti-inflammatory and antibiotic agents were used for 4 weeks. Postoperative Assessments Postoperative examinations were performed more than 1 month after surgery. We measured the refraction spherical equivalent (SE); uncorrected distance VA (UCDVA) and bestcorrected distance VA (BCDVA); uncorrected intermediate VA (UCIVA), distance-corrected intermediate VA (DCIVA), and best-corrected intermediate VA (BCIVA) at 50 cm and 1 m; and uncorrected near VA (UCNVA), distance-corrected near VA (DCNVA), and best-corrected near VA (BCNVA) at 40 and 30 cm. All VAs were measured monocularly and binocularly using the Landolt decimal VA chart. The VA was converted to the logarithm of the minimum angle of resolution (logmar). The results are expressed as the mean T SD. The contrast sensitivity, depth of focus, binocular depth perception function, and spectacle independence were also assessed. Contrast sensitivity and depth of focus were measured without refractive correction. The contrast sensitivity function was measured using the CSV-1000 system (Vector Vision, Inc) under background illumination of 85 cd/m 2. Near stereopsis was measured using the Titmus stereoscopic test with nonrefractive correction and near full refractive correction. Patient satisfaction was evaluated using a questionnaire with 3 options: not satisfied, satisfied, and very satisfied. Statistical Analysis Regarding VAs and contrast sensitivity, the differences in monocular and binocular levels were compared using the Kruskal-Wallis and Steel-Dwass multiple tests. A P value less than 0.05 was considered statistically significant. RESULTS The mean SE of eyes with the SN6AD1 IOL was 0.18 T 0.31 D, and of eyes with the SN6AD3 IOL was 0.22 T 0.46 D. There was no significant difference between eyes with the SN6AD1 and eyes with SN6AD3 (unpaired t test, P =0.791). The mean VAs are shown in Table 2. The binocular UCDVA was significantly better than the monocular UCDVA with the SN6AD3 IOL (Steel-Dwass, P = 0.037). The binocular UCNVA at 30 cm was significantly better than the monocular UCNVA in eyes with the SN6AD1 IOL (Steel-Dwass, P = 0.008), and the binocular DCNVA at 30 cm was significantly better than the monocular DCNVA in eyes with the SN6AD1 (Steel-Dwass, P = 0.023). Regarding the UCIVA at 50 cm, the binocular DCIVA at 50 cm was significantly better than the monocular DCIVA of eyes with the SN6AD3 IOL (Steel- Dwass, P= 0.039). Depth of Focus The depth of focus results are shown in Figure 1. The monocular depth of focus curve in eyes with the SN6AD1 IOL had double peaks with the 0 D and j2.0 D addition powers. The monocular depth of focus curve in eyes with the SN6AD3 IOL had double peaks with the 0 D and j3.0 D addition powers. The binocular depth of focus showed overlapping curves with the monocular depth of focus in eyes with the SN6AD1 IOL and in eyes with the SN6AD3 IOL. The decrease between j1.0 D and j2.0 D was smaller than the monocular depth of focus in both the eyes implanted with the SN6AD1 and SN6AD3 IOLs. Contrast Sensitivity Figure 2 shows that the mean contrast sensitivities postoperatively were within the normal range at all spatial frequencies. There were no significant differences at each spatial frequency in binocular VA or monocular VA in eyes with the SN6AD1 and the SN6AD3 IOLs (3 cpd: P = 0.218; 6 cpd: P = 0.309; 12 cpd: P = 0.075; 18 cpd: P = 0.508). Near Stereopsis All except 1 patient were within the normal range (less than 100 seconds of arc) with both nonrefractive correction and near full-refractive correction. Spectacle Wear All patients were spectacle independent and expressed high satisfaction. No patients reported differences in distance vision, including photopic phenomena, between the eye implanted with the SN6AD1 IOL and the eye implanted with the SN6AD3 IOL * 2015 Asia Pacific Academy of Ophthalmology

3 Asia-Pacific Journal of Ophthalmology & Volume 4, Number 6, November/December 2015 Visual Performance After Implantation of IOL TABLE 2. Postoperative Mean Visual Acuities Current Study Previous Study* Monocular Vision Bissen-Miyajima et al 10 SN6AD1 SN6AD3 Binocular Vision SN6AD1 Distance UCVA T T T T 0.13 BCVA T T T T 0.0 Near (30 cm) UCVA T T T NA DCVA T T T NA BCVA T T T NA Near (40 cm) UCVA T T T T 0.08 DCVA T T T T 0.08 BCVA T T T T 0.07 Intermediate (50 cm) UCVA T T T T 0.14 DCVA T T T T 0.11 BCVA T T T NA Intermediate (1 m) UCVA T T T T 0.13 DCVA T T T T 0.11 BCVA T T T NA UCVA indicates uncorrected visual acuity; BCVA, best-corrected visual acuity; DCVA, distance-corrected visual acuity; NA, data not available. *Bilateral implantation of SN6AD1 IOLs. Patient Satisfaction Ten (90.9 %) of 11 patients replied to the questionnaire as very satisfied, and 1 (9.1%) patient replied as satisfied. No patients replied as not satisfied. DISCUSSION The aim of multifocal IOL implantation is to reduce spectacle dependence, and the optimal reading distance must be considered to increase patient satisfaction. Reading distances vary depending on the patients lifestyles. Myopic eyes tend to have a closer reading distance than hyperopic eyes. Thus, in highly myopic eyes, a multifocal IOL with a +3.0 D addition provides good intermediate vision, but the reading distance might be too far. Patients who need to read fine print in daily life also prefer a closer reading distance. The reading distance with a multifocal IOL with a +4.0 D addition is adequate in these cases. However, for intermediate VA, bilateral implantation of a multifocal IOL with a +4.0 D addition is worse than bilateral implantation of a multifocal IOL with a +3.0 D addition. 6,9 In the current study, the binocular VA results were equal to or better than the monocular results with both IOL models at all distances, and the binocular depth of focus showed overlapping curves with the monocular depth of focus in both eyes. These results may indicate that contralateral implantation of the ReSTOR aspheric SN6AD1 and SN6AD3 IOLs reaps the FIGURE 1. Binocular depth of focus curve and monocular depth of focus curves in eyes implanted monocularly with the SN6AD1 IOL and the SN6AD3 IOL. FIGURE 2. Postoperative binocular contrast sensitivity and contrast sensitivity in eyes implanted monocularly with the SN6AD1 IOL and the SN6AD3 IOL. OD indicates right eye; OS, left eye. * 2015 Asia Pacific Academy of Ophthalmology 331

4 Nakamura et al Asia-Pacific Journal of Ophthalmology & Volume 4, Number 6, November/December 2015 benefits of both designs. To evaluate these results, the effect of binocular summation should be considered. Regarding binocular VA in the current study, contralateral implantation of the ReSTOR aspheric SN6AD1 and SN6AD3 IOLs showed similar results to those of a previous study 10 of bilateral implantation of the SN6AD1 IOL at distances from 40 cm to 1 m (Table 2). The binocular VA at 30 cm could not be compared because there were no data on bilateral implantation of the SN6AD1 IOL at that distance. In the current study, all patients who underwent contralateral implantation of the ReSTOR aspheric SN6AD1 and SN6AD3 IOLs could read and do computer work without spectacles. This result seems better than the previously mentioned reports 7,9,10 of bilateral implantation of the SN6AD1 IOL. Compared with bilateral implantation of the SN6AD1 IOL, contralateral implantation of the SN6AD1 and SN6AD3 IOLs may reduce near stereopsis due to anisometropia with near vision; in the current study, all except 1 patient were within the normal range under nonrefractive correction. Finkelman et al 17 reported that modest monovision (defocus of 1.0 to 1.5 D) can achieve fine stereopsis. The near vision defocus with contralateral implantation of the SN6AD1 and SN6AD3 IOLs was 1.0 D, and the previous report may support our result for near stereopsis. A mix-and-match technique, that is, implantation of a refractive multifocal IOL, monofocal IOL, or an accommodative IOL in 1 eye and a diffractive multifocal IOL in the contralateral eye, has also been suggested to improve intermediate vision. 11Y15 However, this may be unsuitable for most patients because the images provided by those 2 IOL types differ substantially. For example, the severity of halos with refractive IOLs is higher than with diffractive IOLs. 18,19 Pepose et al 15 reported that the combined implantation of an accommodative IOL and diffractive IOL was rated less favorably than the bilateral implantation of accommodative IOLs or diffractive IOLs on patient quality of vision questionnaires. Aging has a well-known effect on pupillary size, 20Y22 and both photopic and scotopic pupillary sizes decrease with age up to 60 years. 22 The near VA decreased with pupils smaller than 4.5 mm in patients with a refractive IOL. With the onset of presbyopia, the pupillary size for viewing a near target was significantly smaller compared with younger age groups, and the indication for refractive multifocal IOLs waslessthan60%. 22 Rabsilber et al 16 reported the contralateral implantation of refractive multifocal IOLs with +3.0 D and +4.0 D additions, and they did not find any advantages compared with bilateral implantation of refractive multifocal IOLs with +3.0 D. Their patients ranged in age from 53 to 84 years, therefore pupillary size issues may diminish the advantages of refractive multifocal IOLs with +4.0 D addition. They also reported that the binocular defocus curve of the contralateral implantation of refractive multifocal IOLs with +3.0 D and +4.0 D additions showed a higher peak at distance vision and a lower peak at near vison. 16 In our data, the binocular defocus curve of the contralateral implantation of ReSTOR aspheric IOLs with +3.0 D and +4.0 D additions showed double peaks of the same height for distance and near vision. The near light distribution of refractive multifocal IOLs is smaller than in diffractive multifocal IOLs, which may also obscure the benefits of the contralateral implantation of refractive multifocal IOLs. Recently, trifocal IOLs have been developed for improving intermediate vision. However, creating a third focus decreases the amount of energy allocated to the far and near foci and may interfere with contrast sensitivity, especially for distance vision in patients with smaller pupils. 23 In the current study, no patients reported a difference in distance vision, including photopic phenomena, between the eye implanted with the SN6AD1 IOL and the eye implanted with the SN6AD3 IOL. A recent study reported that the differences in the optics between the +3.0 D addition IOL and the +4.0 D addition IOL (ie, the number of concentric steps) does not affect image quality, and there were no differences between IOLs with a +3.0 D addition and those with a +4.0 D addition in contrast sensitivity, halos, and glare. 24 Thus, contralateral implantation of ReSTOR aspheric IOLs with +3.0 D and +4.0 D additions may be effective for patients who require a broader range of good uncorrected near VA. Patient demands are diversifying, and some patients may prefer intermediate vision over near vision. In that case, the combination of an IOL with +3.0 D addition and an IOL with a lower addition power may be effective. Consultation after the first eye surgery may be essential for introducing contralateral implantation of multifocal IOLs with different addition powers. Regarding monovision, patients with weak ocular dominance are good candidates and patients with strong ocular dominance are not. 25 Strong ocular dominance causes insufficient blur suppression and results in decreased patient satisfaction. In the current study, patient satisfaction was high for near vision, but strong ocular dominance may affect satisfaction with near vision after the contralateral implantation of multifocal IOLs. Unfortunately, the number of patients was limited because our study was retrospective, and our standard surgery involves bilateral implantation of multifocal IOLs of the same addition. A prospective study with a large number of subjects is needed to ascertain our findings. In conclusion, the results of the current study indicate that contralateral implantation of ReSTOR aspheric IOLs with +3.0 D and +4.0 D additions provided a broad range of near focus and maintained good uncorrected distance vision and may be considered an option for certain patient lifestyles. REFERENCES 1. Alfonso JF, Fernández-Vega L, Baamonde MB, et al. Prospective visual evaluation of apodized diffractive intraocular lenses. J Cataract Refract Surg. 2007;33:1235Y Chiam PJ, Chan JH, Aggarwal RK, et al. ReSTOR intraocular lens implantation in cataract surgery: quality of vision. J Cataract Refract Surg. 2006;32:1459Y Chiam PJ, Chan JH, Haider SI, et al. Functional vision with bilateral ReZoom and ReSTOR intraocular lenses 6 months after cataract surgery. J Cataract Refract Surg. 2007;33:2057Y Cillino S, Casuccio A, Di Pace F, et al. 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