Visual function after bilateral implantation of a new zonal refractive aspheric multifocal intraocular lens

ARTICLE Visual function after bilateral implantation of a new zonal refractive aspheric multifocal intraocular lens Gonzalo Mu~noz, MD, PhD, FEBO, Cesar Albarran-Diego, MSc, Teresa Ferrer-Blasco, PhD, Hani F. Sakla, MD, PhD, Santiago García-Lazaro, PhD PURPOSE: To evaluate visual function after bilateral implantation of a zonal refractive aspheric multifocal intraocular lens (IOL). SETTING: Private practice surgery center, Valencia, Spain. DESIGN: Cohort study. METHODS: Consecutive eyes with cataract had bilateral implantation of Lentis Mplus LS-312 multifocal IOLs. Distance, intermediate, and near visual acuities; contrast sensitivity; defocus curves; and a quality-of-vision questionnaire, including presence of halos or dysphotopsia, were evaluated 6 months postoperatively. A control group of age-matched monofocal pseudophakic patients was included to compare contrast sensitivity function. RESULTS: In the multifocal group, the mean binocular corrected distance visual acuity (logmar) was 0.04 G 0.07 at 6 m, 0.11 G 0.10 at 1 m, and 0.06 G 0.07 at 40 cm. The defocus curve showed little intermediate vision drop off. Photopic contrast sensitivity for distance was similar to the monofocal IOL contrast sensitivity function, while photopic contrast sensitivity for near and mesopic contrast sensitivity for distance with or without glare was reduced at high frequencies. The mean patient satisfaction was 8.09 G 1.30 (scale 0 to 10); 84.4% of patients were completely independent of spectacles. Moderate halos, glare, and night-vision problems were reported by 6.2%, 12.5%, and 15.6% of patients, respectively. CONCLUSION: The new-generation multifocal IOL provided adequate distance, intermediate, and, to a lesser extent, near vision with high rates of spectacle freedom. Halos occurred, and other photic phenomena should be expected in a small percentage of patients. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2011; 37:2043 2052 Q 2011 ASCRS and ESCRS Implantation of intraocular lenses (IOLs) to obtain refractive correction for all distances is the goal of lens-based refractive surgery. Several multifocal IOL designs have been introduced; these include diffractive, zonal refractive, hybrid refractive diffractive, and pseudoaccommodating IOLs. 1 10 Previous studies 11,12 report better uncorrected near and intermediate vision with multifocal IOLs than with monofocal IOLs and comparable distance acuity. However, a lack of satisfaction with the outcomes of multifocal IOL implantation is a relatively frequent report by patients who do not achieve visual goals, have limited quality of vision, or develop new optical aberrations. 5,13 The Lentis Mplus (Oculentis GmbH) is a new singlepiece refractive multifocal IOL with an aspheric posterior surface. The multifocality is achieved with a near vision sector of C3.00 diopters (D) in the lower IOL segment, as in a bifocal ophthalmic lens, yielding C2.50 D at the spectacle plane. The new IOL is based on the concept of rotational asymmetry; the IOL is divided into 2 radial sectors, 1 for distance vision and 1 for near vision, both on the optical axis of the lens. The light is refracted to the near focus in a specific sector only, and the rest of the lens acts as a monofocal IOL. The potential advantages of this approach include more light to the distance focus with improved contrast sensitivity, less halo and glare, and better Q 2011 ASCRS and ESCRS Published by Elsevier Inc. 0886-3350/$ - see front matter 2043 doi:10.1016/j.jcrs.2011.05.045

2044 VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL image quality, avoiding the effect of light scatter due to diffraction. 14 Comparison of this new-generation rotational asymmetric multifocal IOL with a monofocal IOL has been performed 14 ; however, the study did not include subjective assessment of photic phenomena postoperatively. The aim of the present study was to evaluate the clinical performance of the Lentis Mplus LS-312 multifocal IOL, including photic phenomena assessment. PATIENTS AND METHODS Enrollment and Baseline This prospective consecutive nonrandomized interventional clinical study comprised patients having bilateral cataract surgery with implantation of a rotationally asymmetric multifocal IOL. All patients provided written informed consent before surgery in accordance with the Declaration of Helsinki, and institutional review board approval was obtained from the hospital ethics committee. Inclusion criteria were cataract causing a significant reduction in visual quality, potential visual acuity determined by dilated near-pinhole test 15 of 0.3 logmar or better, and corneal astigmatism of 1.00 D or less in both eyes. Exclusion criteria were ocular disease other than cataract, including uveitis, amblyopia, glaucoma, retinal detachment, diabetic retinopathy, macular degeneration, corneal opacities, previous corneal refractive surgery, and neuro-ophthalmic disease. Preoperatively, all patients had a full ophthalmologic examination including refractive status; distance, intermediate, and near monocular visual acuities; slitlamp evaluation; tonometry; and fundoscopy. The uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) at 6 m and the uncorrected intermediate visual acuity (UIVA) and distance-corrected intermediate visual acuity (DCIVA) at 2 m, 1 m, and 70 cm were assessed using a calibrated Snellen chart. Uncorrected near visual acuity (UNVA), distance-corrected near visual acuity (DCNVA), and corrected near visual acuity (CNVA) using a C2.50 D addition (add) over distance correction were tested at 50 cm, 40 cm, and 33 cm with an Early Treatment Diabetic Retinopathy Study chart (Precision Vision). Corneal Submitted: March 16, 2011. Final revision submitted: May 17, 2011. Accepted: May 19, 2011. From the Refractive Surgery Department (Mu~noz, Albarran-Diego), Clınica Oftalmologica Marques de Sotelo, and Hospital NISA Valencia al Mar and the Optometry Research Group (GIO) (Ferrer-Blasco, Garcıa-Lazaro), University of Valencia, Valencia, Spain; Ebsaar Eye Surgery Center (Mu~noz, Sakla) Dubai, United Arab Emirates. Supported in part by Ministerio de Ciencia e Innovacion Research Grant (SAF2009-13342). Corresponding author: Gonzalo Mu~noz, MD, PhD, FEBO, Clınica Oftalmologica Marques de Sotelo, Avenida Marques de Sotelo 5, Planta 2 a, Pta. 5, 46002 Valencia, Spain. E-mail: gon.munoz@ ono.com. refractive power was measured with an automated keratorefractometer (KR-7000, Topcon), and axial length (AL) was measured using noncontact optical biometry (IOLMaster, Carl Zeiss Meditec AG). The power of the IOL was selected for a target of emmetropia applying the SRK/T formula for eyes with an AL longer than 22.0 mm and the Hoffer-Q formula for eyes with an AL shorter than 22.0 mm. 16 18 An A constant of 118.2 was used. The data-screening criteria proposed by Holladay et al. 19 were used to avoid refractive surprises. Multifocal Intraocular Lens Lentis Mplus (model LS-312MF) is a biconvex 1-piece multifocal acrylic IOL made with an aspheric posterior surface design. The LS-312 MF model has a 12.0 mm overall length, a 6.0 mm optic, and a C-loop haptic design with 0-degree angulation. The nonrotational symmetric multifocal IOL with a refractive design combines an aspheric asymmetric distance vision zone with a sector-shaped near vision zone with a C3.00 D add. Surgical Technique The same surgeon (G.M.) performed all operations; the second-eye surgery was performed within 1 week of the first. The technique included phacoemulsification through a 2.75 mm clear corneal incision placed on the steepest meridian, a 5.0 mm capsulorhexis, and symmetric implantation of the IOL in the capsular bag. The IOLs were implanted according to the manufacturer s instructions using a disposable 2.2 mm injector (Viscoject 2.2 Cartridge-Set, Medicel AG); that is, with the horizontal reference marks in the optic of the IOL placed on the 0- to 180-degree meridian (haptics at 90 to 270 degrees) and thus with the near sector placed inferiorly. Postoperative topical therapy included diclofenac 0.1% (Dicloabak) and tobramycin 0.3% dexamethasone 0.1% (Tobradex) for 3 weeks. Postoperative Assessments Evaluations were performed 1 day, 1 week, and 1, 3, and 6 months after the second-eye surgery and included refractive status, slitlamp evaluation, tonometry, and fundoscopy. Monocular and binocular UDVA, CDVA, UIVA, and DCIVA at 2 m, 1 m, and 70 cm and UNVA, DCNVA, and CNVA at 50 cm, 40 cm, and 33 cm were recorded. To generate defocus curves, monocular visual acuity was measured with the Snellen chart at 6 m using a variety of lens powers in a phoropter. Patients were defocused to 5.00 D spherical from the manifest refraction values, after which logmar acuity was recorded. Added negative spherical power was progressively reduced in 0.50 D steps; logmar acuity was recorded after every step until the original manifest refraction values were reached. Patients were then defocused to C3.00 D spherical from the manifest refraction, and logmar acuity was again recorded. Positive spherical power was progressively reduced in 0.50 D steps and logmar acuity recorded after every step until manifest refraction values were reached. Contrast sensitivity was tested monocularly for distance and near vision with best correction for distance under photopic conditions (90 candelas [cd]/m 2 ) and for distance with and without glare under mesopic conditions (5 cd/m 2 ) using a Functional Acuity Contrast Test (Stereo Optical Co., Inc.). 20 This test allows the presentation of sine-wave gratings at

VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL 2045 different spatial frequencies (1.5, 3, 6, 12, and 18 cycles per degree [cpd]), with increasing contrast values. Absolute values of log 10 contrast sensitivity were obtained for each combination of eye and spatial frequency, and means and standard deviations (SD) were calculated. An HD 9221 photometer (Delta OHM S.r.L.) was used to measure the lighting conditions in the room in which contrast sensitivity was measured to ensure equal lighting levels for all patients at all testing sessions. Under photopic conditions, luminance was 90 cd/m 2 and illumination was 450 lux. Mesopic conditions were 5 cd/m 2 and 4 lux. 21 Patients remained 10 minutes inside the testing room under mesopic conditions for an appropriate adaptation before mesopic contrast sensitivity was measured. Contrast sensitivity with appropriate correction for distance and near was measured in a control group of age-matched pseudophakic patients with the AR-40e monofocal IOL (Abbott Medical Optics, Inc.). Posterior capsule opacification (PCO), IOL centration, and tilt were assessed at 6 months. Posterior capsule opacification was graded as follows: 1 Z none, 2 Z mild (early development of PCO), 3 Z moderate (increased PCO with early visual acuity changes not requiring secondary capsulotomy), and 4 Z severe (PCO affecting vision and requiring neodymium:yag laser capsulotomy). Quality-of-Vision Questionnaire At the final follow-up visit after 6 months, all patients completed a 14-item questionnaire that included the following: 1. The presence of visual disturbances or photic phenomena (4 items): glare (trouble seeing street signs due to bright light on oncoming headlights), halos (rings around lights), double vision, and night-vision difficulties. 2. Visual lifestyle activities (6 items): watching television, driving at night, using a computer, reading, using a cell phone, and shaving/putting on makeup. 3. Spectacle independence for distance, intermediate, and near vision (3 items). 4. Overall satisfaction (1 item). The response rating scale for visual disturbance and lifestyle activity items was 0 Z no difficulty, 1 Z minimal difficulty, 2 and 3 Z moderate difficulty, and 4 and 5 Z severe difficulty. The response rating scale for spectacle use items was 0 Z never, 1Z rarely or occasionally, 2 Z often, and 3 Z always. The response rating scale for overall satisfaction was from 0 (least satisfied) to 10 (most satisfied). This questionnaire is a summarized version of one used by Kohnen et al., 22 which is in turn based on the survey distributed in the U.S. Food and Drug Administration clinical trials for the Alcon Acrysof IQ Restor in the National Eye Institute Visual Functioning Questionnaire-25, 23 and the Cataract TYPE questionnaire. 24 Data Management and Statistical Analysis Visual acuity values were converted to logmar notation for statistical purposes. For intermediate visual acuities at 2 m, 1 m, and 70 cm and for near visual acuities at 50 cm and 33 cm, scales were corrected accordingly as previously described. 25 Logarithmic scales were used for statistical and graphical purposes with regard to contrast sensitivity data. Manifest refractions were converted into power vector coordinates as proposed by Thibos and Horner. 26 The revised abbreviations for reporting visual acuity values proposed by Kohnen 27 were used. Statistical analysis was performed using SigmaPlot software (version 11, Systat Software, Inc.). The normality of all data samples was evaluated with the Kolmogorov-Smirnov test. The Student t test for paired data was used for all parameter comparisons between preoperative and postoperative examinations. The Student t test for unpaired data was used for comparisons of contrast sensitivity between the multifocal IOL group and the monofocal IOL group. Results are presented as the mean G SD; a P value of 0.05 was considered statistically significant. RESULTS Data were collected from 64 eyes of 32 patients (18 men, 14 women) with a mean age of 63.6 G 9.1 years (range 48 to 71 years). The mean pupil size was 3.4 G 0.8 mm under photopic conditions and 5.3 G 0.7 mm under mesopic conditions. The mean preoperative spherical equivalent (SE) was 1.30 G 2.56 D; 47 eyes (73%) were hyperopic, 12 (19%) were myopic, and 5 (8%) were emmetropic. The age-matched control group (with monofocal IOL) comprised 64 eyes of 32 patients. Adverse Events and Posterior Capsule Assessments There were no intraoperative complications. There were no cases of iris trauma, IOL decentration, or IOL tilt. Two patients had minor adverse events; 1 had bilateral dry eye requiring punctual plug insertion and 1 reported bilateral dysphotopsia in the form of monocular diplopia. At 6 months, 59 eyes (92.2%) had no or mild PCO, 4 eyes (6.3%) had grade 3 PCO, and 1 eye (1.5%) had grade 4 or severe PCO requiring capsulotomy. Refraction The postoperative refraction was close to emmetropia (mean SE [M] 0.30 G 0.33 D). There was no induced astigmatism as a consequence of cataract surgery and no significant changes in J0 or J45 components of astigmatism after vector decomposition (Table 1). Fifty-eight eyes (90.6%) were within G0.50 D of the target SE, and all the eyes were within G1.00 D. The 6 eyes (9.4%) with an SE higher than G0.50 D were all myopic with a mean residual SE of 0.75 G 0.15 D. Distance, Intermediate, and Near Vision Table 1 compares the monocular logmar visual acuity values before surgery and 6 months after surgery in eyes with the multifocal IOL, and Table 2 shows the monocular and binocular logmar visual acuity values at all tested distances. Postoperatively, there was a statistically significant improvement in monocular logmar UDVA, monocular logmar

2046 VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL Table 1. Comparison of preoperative and 6-month postoperative data after bilateral multifocal IOL implantation. Parameter Mean G SD Preoperative Postoperative P Value Refraction (D)* M 1.30 G 2.56 0.30 G 0.33!.001 J0 0.12 G 0.26 0.09 G 0.13.18 J45 0.05 G 0.29 0.06 G 0.11.42 LogMAR UDVA 0.49 G 0.48 0.05 G 0.10!.0001 LogMAR CDVA 0.39 G 0.44 0.02 G 0.05!.0001 LogMAR UNVA 0.53 G 0.39 0.11 G 0.13!.0001 LogMAR DCNVA 0.62 G 0.50 0.07 G 0.07!.0001 LogMAR CNVA 0.33 G 0.34 0.00 G 0.06!.0001 LogMAR UIVA (1 m) 0.56 G 0.64 0.13 G 0.12!.0001 LogMAR DCIVA (1 m) 0.53 G 0.54 0.14 G 0.08!.0001 IOL power (D) 20.5 G 2.1 d d IOP (mm Hg) 16.2 G 5.3 15.5 G 5.8.23 CDVA Z corrected distance visual acuity; CNVA Z corrected near visual acuity; DCIVA Z distance corrected intermediate visual acuity; DCNVA Z distance corrected near visual acuity; IOL Z intraocular lens; IOP Z intraocular pressure; UDVA Z uncorrected distance visual acuity; UIVA Z uncorrected intermediate visual acuity; UNVA Z uncorrected near visual acuity *Manifest refractions in conventional script, sphere (S), cylinder (C) and axis (f) were converted into power vector coordinates (M, J0, J45) by the following formulas: M Z S C C/2; J0 Z ( C/2) cos (2f); J45 Z ( C/2) sin (2f). Paired Student t test CDVA, monocular logmar UNVA, monocular logmar DCNVA, and monocular logmar CNVA (all P!.01, paired Student t test). There were also statistically significant improvements in monocular log- MAR UIVA and DCIVA at 1 m (both P!.01, paired Student t test). Uncorrected visual acuity in decimal notation was at least 0.5 at near and distance in more than 98% of eyes and at all 3 intermediate distances in 76% of eyes. In the 6 eyes with a residual SE higher than 0.50 D, the mean logmar UDVA was 0.08 G 0.06 (0.83 G 0.59 lines decimal), the mean logmar UIVA at 1 m was 0.04 G 0.05 (0.91 G 0.52 lines decimal), and the mean logmar UNVA at 40 cm was 0.13 G 0.07 (0.74 G 0.65 lines decimal). This indicates that the tolerance to myopic defocus after multifocal IOL implantation was excellent. The correlation between logmar CDVA and photopic pupil size was low (r Z 0.15) and not statistically significant (PZ.23). The same was true for logmar DCNVA and photopic pupil size (r Z 0.09; PZ.52). Defocus Curve The defocus curve in Figure 1 has 2 peaks of maximum vision located at the far and near foci corresponding to 0.00 D and 2.50 D defocus, respectively, with reduced visual acuity for intermediate distances. The defocus curve has a peak of optimum near vision (mean 0.07 G 0.07 logmar) at the vergence of 2.50 D, the equivalent of 40 cm from the eye. The minimum intermediate vision occurs at a vergence of 1.00 D, or 1 m from the eye. Even so, the mean intermediate visual acuity at this point on the defocus curve (0.14 G 0.08 logmar) remains good. Contrast Sensitivity Photopic distance contrast sensitivity in the multifocal IOL group was similar to that in the monofocal IOL control group (Figure 2, top), with no statistically significant differences at any tested frequency Table 2. Monocular and binocular visual acuity at far, intermediate, and near 6 months after multifocal IOL implantation. Intermediate Near Parameter Far (6 m) (2 m) (1 m) (70 cm) (50 cm) (40 cm) (33 cm) Monocular uncorrected VA LogMAR 0.05 G 0.10 0.03 G 0.11 0.13 G 0.12 0.14 G 0.11 0.11 G 0.10 0.11 G 0.13 0.09 G 0.11 Decimal 0.89 G 1.03 0.93 G 1.06 0.74 G 1.17 0.72 G 1.08 0.77 G 1.03 0,79 G 1,26 0.80 G 1.09 Monocular distance-corrected VA LogMAR 0.02 G 0.05 0.06 G 0.10 0.14 G 0.08 0.13 G 0.09 0.09 G 0.06 0.07 G 0.07 0.14 G 0.11 Decimal 1.05 G 0.52 0.87 G 0.98 0.72 G 0.81 0.74 G 0.92 0.81 G 0.64 0.85 G 0.71 0.72 G 1.09 Binocular uncorrected VA LogMAR 0.03 G 0.11 0.02 G 0.12 0.13 G 0.09 0.13 G 0.10 0.09 G 0.10 0.09 G 0.12 0.10 G 0.11 Decimal 0.93 G 1.07 0.96 G 1.17 0.74 G 0.94 0.74 G 0.98 0.81 G 0.97 0.82 G 1.24 0.80 G 1.07 Binocular distance-corrected VA LogMAR 0.04 G 0.07 0.03 G 0.09 0.11 G 0.10 0.12 G 0.07 0.08 G 0.08 0.06 G 0.07 0.10 G 0.06 Decimal 1.10 G 0.68 0.92 G 0.87 0.78 G 0.95 0.76 G 0.72 0.83 G 0.83 0.87 G 0.72 0.79 G 0.63 VA Z visual acuity

VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL 2047 Figure 1. Defocus curve for the Lentis Mplus IOL 6 months after implantation. The error bars represent G SD values for each vergence. (1.5 cpd, PZ.23; 3 cpd, PZ.49; 6 cpd, PZ.71; 12 cpd, PZ.20, 18 cpd, PZ.10). Photopic near contrast sensitivity (Figure 2, bottom) was similar at low frequencies (1.5 cpd, PZ.20; 3 cpd, PZ.71; 6 cpd, PZ.34) but was significantly lower than contrast sensitivity function with the monofocal IOL at 12 cpd and 18 cpd (both P!.01). Under mesopic conditions without glare (Figure 3, top), distance contrast sensitivity with the multifocal IOL was similar to that of the monofocal IOL at low frequencies (1.5 cpd, PZ.12; 3 cpd, PZ.12; 6 cpd, PZ.09) but was significantly lower at high spatial frequencies (12 cpd and 18 cpd; both P!.01). The same was true for distance contrast sensitivity under mesopic conditions with glare (Figure 3, bottom), with no significant differences at 1.5 cpd (PZ0.14) and 3 cpd (PZ.14) but with statistically significant lower values at higher frequencies (6 cpd, 12 cpd, and 18 cpd; all P!.01). Visual Disturbances and Photic Phenomena The mean score for glare, halos, double vision, and night-vision disturbances indicated minimum to no difficulty at the 6-month follow-up (Table 3). Five (15.6%) patients reported moderate night-vision problems, 4 (12.5%) reported moderate glare, 2 (6.2%) reported moderate halos, and 1 (3.1%) had monocular double vision in both eyes that caused moderate impairment. No patient reported severe difficulty for any of the 4 visual disturbance items evaluated. Visual Lifestyle Activities At 6 months, no patient reported severe difficulty with any of the 6 lifestyle activities evaluated. None reported moderate problems for watching television (distance vision) or using a computer (intermediate vision). Moderate difficulties were reported by 3 (12.5%) of 24 patients for driving at night, 7 (21.9%) of 32 patients for reading or near work, 4 (12.5%) of 32 patients for shaving/applying makeup, and 6 (20.0%) of 30 patients for using a cell phone. Spectacle Independence and Overall Patient Satisfaction Of the 32 patients, 27 (84.4%) were completely independent of spectacles for distance, intermediate, and near vision. Thirty-one (96.9%) patients never used glasses for distance vision, 31 (96.9%) never used them for intermediate vision, and 27 (84.4%) never used them for near vision. One (3.1%) patient needed glasses often or always for distance vision, 1 (3.1%) for intermediate vision, and 4 (12.5%) for near vision. Twenty-five (78.1%) rated satisfaction as 8 or higher and 2 (6.2%) as lower than 6. DISCUSSION Visual complaints after multifocal IOL implantation fall into 2 categories. The first is decreased vision for distance, intermediate, or near as a consequence of diminished contrast sensitivity. 5 The second is photic phenomena, including glare, halos, and positive dysphotopsia, or perception of lights, sparks, lines, or colors in some parts of the visual field. 2,11 Contrast sensitivity can decrease up to 50% with some models of multifocal IOLs, 5 and it has been reported that photic phenomena are 3.5 times more likely with multifocal IOLs than with monofocal IOLs. 11 The Lentis Mplus is an acrylic nonrotational symmetric multifocal IOL designed to overcome the drawbacks of multifocal IOLs by providing high contrast sensitivity and minimizing halos and glare. The lens has a refractive design combining an aspheric asymmetric distance vision zone with a sector-shaped

2048 VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL Figure 2. Photopic log contrast sensitivity function at far and near distances in the multifocal IOL group and the monofocal IOL control group. The asterisk represents statistically significant differences between IOLs. The error bars represent G SD values at each spatial frequency (cpd Z cycles per degree). Figure 3. Mesopic log contrast sensitivity function at far and near distances in the multifocal IOL group and the monofocal IOL control group. The asterisk represents statistically significant differences between IOLs. The error bars represent G SD values at each spatial frequency (cpd Z cycles per degree). near vision zone with a C3.00 D add. In the present study, cataract surgery using this new IOL was very predictable. The refractive outcomes were close to emmetropia in all cases, with a mean residual SE near 0.25 D and with only 6% of eyes having a defocus higher than 0.75 D. The distance, intermediate, and, to a lesser extent, near vision results were excellent in our study. The uncorrected visual acuity in decimal notation was at least 0.50 for near and distance in more than 98% of eyes, with a mean binocular logmar UDVA of 0.03 (0.93 decimal). The IOL also performed well for near vision, with a mean binocular logmar UNVA of 0.09 (0.82 decimal) at 40 cm, which was the best distance for near. After distance correction, the mean binocular logmar CDVA and DCNVA improved to 0.04 and 0.06, respectively (1.10 and 0.87 decimal, respectively). The far vision achieved with the Lentis Mplus IOL was comparable to that with other multifocal IOLs, and near vision was somewhat worse. 2,22,28,29 Several studies report that diffractive and hybrid refractive diffractive multifocal IOLs provide better near vision. de Vries et al. 6 and Kohnen et al. 22 report binocular logmar UNVA and DCNVA near 0.00 (1.00 decimal) using the Acrysof Restor SA60D3 IOL and Acrysof Restor SN6AD1 IOL (both Alcon Laboratories, Inc.), respectively. Similar results (binocular decimal DCNVA approximately 1.0) were reported by Cillino et al. 2 using the multifocal diffractive pupil-independent Tecnis ZM900 IOL (Abbott Medical Optics, Inc.) and by Alfonso et al. 28 and Kaymak and Mester 29 using the multifocal diffractive Acri.Lisa 376D IOL (Carl Zeiss Meditec AG). The most likely cause of the worse near vision with the Lentis Mplus IOL is its C3.00 D add, which is lower than the addition of the aforementioned diffractive models except the new C3.00 D Acrysof Restor. Intermediate vision was excellent with the Lentis Mplus IOL. The uncorrected decimal visual acuity was at least 0.5 at all 3 intermediate distances tested

VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL 2049 Table 3. Mean scores for visual disturbances, visual lifestyle activities, spectacle use and overall satisfaction scores 6 months multifocal IOL implantation. Item Mean Score G SD* Visual disturbances (from 0 to 5) Glare 0.69 G 0.86 Halos 0.38 G 0.71 Double vision 0.25 G 0.62 Night vision 0.84 G 0.92 Visual lifestyle activities (from 0 to 5) Watching television 0.28 G 0.46 Driving at night 0.75 G 0.68 Using a computer 0.31 G 0.47 Reading or sewing 1.28 G 0.99 Using a cell phone 1.10 G 1.06 Shaving or putting on makeup 0.88 G 0.87 Spectacle use (from 0 to 3) For distance vision 0.06 G 0.35 For intermediate vision 0.06 G 0.35 For near vision 0.28 G 0.81 Overall satisfaction (from 0 to 10) 8.09 G 1.30 *The response rating scales: visual disturbance and lifestyle activities, 0 Z no difficulty, 1 Z minimal difficulty, 2 and 3 Z moderate difficulty, 4 and 5 Z severe difficulty; spectacle use, 0 Z never, 1 Z rarely or occasionally, 2 Z often and 3 Z always; overall satisfaction, range from 0 (least satisfied) to 10 (most satisfied) (70 cm, 1 m, and 2 m) in 76% of eyes. The mean decimal DCIVA was higher than 0.7 at all intermediate distances (0.74 at 70 cm, 0.72 at 1 m, 0.87 at 2 m). The intermediate vision performance of this multifocal IOL seems better than that reported for diffractive multifocal models, which usually provide excellent distance and near vision with a drop in intermediate vision, causing intermediate blur in some cases. 30,31 Recently, there has been a trend toward reducing the power of the near add (from C 4.00 D to C3.00 D) in some models of diffractive IOLs to improve intermediate vision or expand reading distance 22 ; therefore, the C3.00 D Acrysof Restor IOL models were developed with only 9 diffractive steps that are more widely spaced than the 12 steps of the C4.00 D IOL models. By reducing the addition for near, the near and the far points become closer and the gradual decline in vision between the 2 principal foci is minimized. Intermediate vision with diffractive models has been reported for several distances ranging from 50 to 70 cm. 22,32 34 The C3.00 D diffractive models provide a mean logmar intermediate vision at 50 cm of approximately 0.05 (0.9 decimal), 22 which is much better than the mean logmar intermediate vision at 50 cm provided by the C4.00 D models, which is approximately 0.25 (0.56 decimal). 33 However, even the C3.00 D diffractive models showed a decrease with more extended intermediate vision; at 60 cm and 70 cm, the mean logmar visual acuity fell to approximately 0.12 and 0.20 respectively (0.75 and 0.63 decimal, respectively). 22 Intermediate vision at 1 m was approximately 0.60 decimal, as can be deduced from the defocus curve of the C3.00 D diffractive models. 22 The mean decimal intermediate vision with the Lentis Mplus IOL was 0.74 at 70 cm, 0.72 at 1 m, and 0.87 at 2 m. Thus, the minimum intermediate vision at 1 m was approximately 0.75 decimal, which is better than the intermediate vision reported for C3.00 D diffractive IOLs. We believe it is important to report visual results for intermediate distances of 70 cm and 1 m because they are used in common activities, such as computer work. Refractive multifocal IOL models such as the Rezoom (Abbott Medical Optics, Inc.) are reported to provide intermediate vision similar to that of C3.00 D diffractive IOLs 35 and thus worse than the intermediate vision provided by the Lentis Mplus IOL. One study of C3.50 D refractive IOLs 35 reports a mean UIVA at the preferred intermediate distance (range 60 to 80 cm) of 0.23 logmar (0.59 decimal). Near vision with the Rezoom IOL is reported to be worse than that with IOLs with diffractive designs, as shown in numerous studies 9,10,35,36 ; therefore, this type of IOL has fallen into disuse in multifocal IOL technology. The defocus curve for the Lentis Mplus IOL is consistent with the above findings. The IOL performance for distance was similar to that with a monofocal IOL, with a decimal visual acuity of approximately 1.00. The IOL provided decimal intermediate acuity of approximately 0.70 to 0.80 between 50 cm and 2 m and had the best decimal near vision at 40 cm (mean approximately 0.85). Decimal near vision at 33 cm dropped to approximately 0.75 and dropped further at 25 cm to 0.43. With the multifocal IOL, there was little intermediate drop off at intermediate distances, with the lowest visual acuity threshold at 1 m ( 1.00 D of defocus). Photopic distance contrast sensitivity with the Lentis Mplus multifocal IOL was similar to that with the monofocal IOL, meaning that the multifocal IOL behaves very similarly to a monofocal IOL at distance under high illumination conditions. The photopic near contrast sensitivity was similar between the multifocal IOL and monofocal IOL except at higher frequencies. The mesopic distance contrast sensitivity values also showed differences at high frequencies and at medium and high frequencies in the case of mesopic vision with glare. Alio et al. 14 found similar photopic contrast sensitivity values in a comparison of the Lentis Mplus IOL and a monofocal IOL; they also found a trend (although not significant) toward better contrast sensitivity outcomes

2050 VISUAL PERFORMANCE WITH A NEW BILATERAL ZONAL REFRACTIVE IOL with the monofocal IOL at high spatial frequencies under mesopic conditions. Zhao et al. 37 report similar findings for the C3.00 D Acrysof Restor SA60D3 IOL, which provided reduced contrast sensitivity compared with a monofocal IOL. The reduction in mesopic visual performance at high spatial frequencies may result in a reduced capability to resolve small objects under such conditions; for example, seeing road indications while driving at night. 3,5 Patients with Lentis Mplus IOLs reported a low incidence of significant photic phenomena. Of the patients, 6.2% reported moderate halos, 12.5% reported moderate glare, and 15.6% reported moderate nightvision problems; none of the patients rated these photic phenomena as severe. The subjective scores for halos (0.38 G 0.71), glare (0.69 G 0.86), and night-vision problems (0.84 G 0.92) were low. Using the same scale to subjectively evaluate visual disturbances caused by a diffractive multifocal IOL, Kohnen et al. 22 found a mean score of 1.3 G 1.3 for halos, 1.7 G 1.5 for glare, and 1.1 G 1.4 for night-vision problems, higher than the results in the present study. It therefore seems that the classic disadvantages of multifocal IOL technology, such as halos and glare, are minimized with the Lentis Mplus IOL. Alio et al. 14 found statistically significantly larger amounts of primary coma and tilt with the Lentis Mplus IOL than with a monofocal IOL. In the present study, aberrometry was not performed; therefore, we could not determine whether there was a correlation between postoperative photic phenomena and residual coma or other higher-order aberrations. We did not find a correlation between photic phenomena and residual astigmatism, IOL tilt, or capsulorhexis size. We also did not find a significant correlation between photopic pupil size and CDVA or DCNVA, meaning that the Lentis Mplus IOL showed pupillary independence with the pupil sizes measured in our study. Eighty-four percent of our patients with bilateral Lentis Mplus IOLs achieved full spectacle independence and were satisfied with their distance, intermediate, and near vision. For far vision, 96.9% reported never using glasses. One patient (3.1%) indicated frequent or continued use of glasses for far vision. The outcome in this case was 1.00 D in both eyes. The tolerance of the Lentis Mplus IOL to myopic defocus was excellent. The 6 eyes with a residual SE higher than 0.50 D had excellent UIVA at 1 m and maintained adequate UDVA and UNVA at 40 cm. On the defocus curve, low levels of residual myopia do not translate into a significant decrease in visual performance, which may represent another advantage of this new multifocal IOL design. In the present study, secondary interventions to improve postoperative refractive results were not considered. A secondary excimer laser procedure might have led to a lower percentage of patients needing glasses for distance vision. Similar percentages of spectacle independence for distance vision have been reported for diffractive multifocal models. 22 The percentage of patients free from glasses for intermediate vision activities was 96.9%; 1 patient reported a frequent need for glasses for intermediate distance. This can be easily explained by the defocus curve of the Lentis Mplus IOL in which the typical drop off at intermediate distances seen in other multifocal IOL models is minimized, which we believe is a main advantage of the new IOL. The percentage of patients who never used glasses for near (84.4%) was high, although lower than that reported for diffractive multifocal IOLs. 22 This may be related to the near add of C3.00 D, which yields a C2.50 D add at the spectacle plane; this may be insufficient for some near activities. Regarding the 6 lifestyle activities evaluated in the present study, none of the patients reported moderate or significant problems for activities related to distance vision (eg, watching television) or intermediate vision (eg, using a computer). However, between 12.5% and 21.8% of patients reported moderate difficulties performing activities that require very accurate near vision, such as reading/sewing, text messaging using a cell phone, or shaving/applying makeup. The mean patient satisfaction score was 8.09 G 1.30, with 78% of patients rating satisfaction as 8 or higher. Two patients (6.2%) reported a satisfaction rating lower than 6. 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