The Quest for Spectacle Independence: A Comparison of Multifocal Intraocular Lens Implants and Pseudophakic Monovision for Patients with Presbyopia

ABSTRACT

We performed a literature review comparing multifocal intraocular lens (IOL) implantation with pseudophakic monovision to treat presbyopia. Multifocal IOLs utilize refractive or diffractive principles to treat both distance and near vision, with a single lens implant. Monovision uses traditional monofocal lens implants to treat the dominant eye for emmotropia, and the non-dominant eye for myopia. This planned anisometropia is designed to enhance intermediate or near vision. Generally, distance vision was similar with both types of lens implantation, near vision was better with multifocal IOLs, and intermediate vision appeared to be better in the monovision group. For patients requiring cataract surgery, both multifocal IOLs and monovision appear to address presbyopia with a high level of patient satisfaction. More patients reported complete spectacle independence with multifocal IOLs, but more glare and halos were reported by multifocal IOL patients as well.     

Visual outcomes with multifocal intraocular lenses

Multifocal intraocular lenses (IOLs) are increasingly becoming a part of the armamentarium of cataract and refractive surgeons. Reports show that most multifocal IOLs provide excellent visual outcomes. In one major study of a zonal progressive, refractive, multifocal design, more than 80% of patients were able to see 20/40 or better at distance and J3 or better at near, without correction. This study also found that patients' satisfaction ratings of their multifocal vision were consistently high. Although a few patients with multifocal IOLs complain of halo or glare, these symptoms can be minimized by surgical technique and appropriate selection of the multifocal IOL power.     

Piggyback implantation using the AMO array multifocal intraocular lens

Piggyback intraocular lens (IOL) implantation allows refractive correction in cases in which the IOL power requirement exceeds that of the available lenses. By combining a piggyback technique with the use of a multifocal IOL, one can obtain the optical advantages of both, achieving high-quality visual acuity for distance and near vision and reducing the optical aberrations of extremely high-powered single IOLs. We report 5 hyperopic patients (6 eyes) who had phacoemulsification and in-the-bag implantation of 2 foldable IOLs in the bag, a silicone multifocal IOL placed in front of a silicone monofocal IOL. Good results were obtained in near and distance uncorrected visual acuities, and patient satisfaction was excellent in all cases. However, in 2 cases, the anteriorly placed IOL was exchanged because of incorrect power calculation. Piggyback IOL implantation with a multifocal lens appears to be a safe, efficient procedure and a good refractive solution.     

Challenges and approaches in modern biometry and IOL calculation

The introduction of new intraocular lenses (IOLs), industry marketing to the public and patient expectations has warranted increased accuracy of IOL power calculations. Toric IOLs, multifocal IOLs, aspheric IOLs, phakic lenses, accommodative lenses, cases of refractive lens exchange and eyes that have undergone previous refractive surgery all require improved clinical measurements and IOL prediction formulas. Hence, measurement techniques and IOL calculation formulas are essential factors that affect the refractive outcome.Measurement with ultrasound has been the historic standard for measurement of ocular parameters for IOL calculation. However the introduction of optical biometry using partial coherence interferometry (PCI) has steadily established itself as the new standard. Additionally, modern optical instruments such as Scheimpflug cameras and optical coherence tomographers are being used to determine corneal power that was normally the purview of manual keratometry and topography.A number of methods are available to determine the IOL power including the empirical, analytical, numerical or combined methods. Ray tracing techniques or paraxial approximation by matrix methods or classical analytical ‘IOL formulas’ are actively used in for the prediction of IOL power. There is no universal formula for all cases – phakic and pseudophakic cases require different approaches, as do short eyes, long eyes, astigmatic eyes or post-refractive surgery eyes. Invariably, IOLs are characterized by different methods and lens constants, which require individual optimization. This review describes the current methods for biometry and IOL calculation.     

Long-term experience with mixing and matching refractive array and diffractive CeeOn multifocal intraocular lenses

PURPOSE: To compare visual performance of the refractive Array SA40N and the diffractive CeeOn 811E multifocal intraocular lenses (IOLs) and to evaluate the potential benefits of combining both multifocal IOLs in the same patient. METHODS: Two groups of cataract patients were unilaterally implanted with either the CeeOn diffractive (n = 10) or the Array refractive multifocal IOL (n = 10). Another group was bilaterally implanted with one of each multifocal IOLs (mix & match group, n = 10). Visual acuity, spectacle independence, depth of focus, contrast sensitivity, presence of photic phenomena, and patient satisfaction were assessed postoperatively. RESULTS: All eyes achieved good distance visual acuity but better uncorrected near vision was achieved with the CeeOn diffractive design. Contrast sensitivity with either multifocal IOL was at the lower limit of the normal range but when multifocal IOLs were combined in the same patient, contrast sensitivity was not significantly different from phakic controls. Defocus curves revealed a superiority of CeeOn diffractive design for near and Array refractive design for intermediate but mix & match patients performed better overall than the other patients, particularly for intermediate distances, which was reflected by total independence from spectacles in 90% of patients compared to 60% in the other groups. Visual outcomes remained unchanged over time (1 month vs 6 month vs > 3 years). CONCLUSIONS: Bilateral implantation with a diffractive multifocal IOL in one eye and a refractive multifocal IOL in the fellow eye is safe and could provide patients with better intermediate vision, increased depth of focus and contrast sensitivity, and also less dependence on spectacles.     

Accommodative intraocular lenses: short-term visual results of two different lens types

PURPOSE: To compare the ability of two types of accommodative intraocular lenses (IOLs) to provide uncorrected near and distance visual acuity (VA) after cataract surgery. METHODS: A total of 108 eyes of 75 patients underwent cataract surgery by phacoemulsification and IOL implantation either bilaterally or monocularly with one of two types of accommodative IOLs: the AT-45 lens (69 eyes) or the 1-CU lens (39 eyes). Patients were followed for up to 1 year after cataract surgery. Near VA was measured through the distance correction to obtain the true near vision effect of the accommodating IOL. RESULTS: Uncorrected distance VA of 20/30 or better was achieved by 84.6% of the bilaterally implanted 1-CU patients and 73.6% of the bilaterally implanted AT-45 IOL patients 1 year following surgery. Uncorrected near VA of J1 or better was achieved by 42% of the patients with the bilateral 1-CU implant and 36.8% of the patients with the bilateral AT-45 implant. For J3 or better near acuity, the values were 92.3% for the bilateral 1-CU patients and 84.2% for the bilateral AT-45 patients at 1 year. A total of 54% of the eyes with 1-CU implants underwent a mild myopic shift (<1.0 D), 21% had a mild hyperopic shift, and 45% of the eyes were emmetropic at 1 year. CONCLUSIONS: Both accommodative IOLs provided good near and distance vision postoperatively. The 1-CU IOL appears clinically to provide slightly better uncorrected distance and distance-corrected near VA than the AT-45 lens.     

Quality of vision after AMO Array multifocal intraocular lens implantation

PURPOSE: To evaluate safety and efficacy of Array SA40N multifocal intraocular lens (IOL) (AMO) implantation in cataract surgery. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: In this prospective randomized comparative trial, 80 patients scheduled for cataract surgery were selected based on preoperative counseling and randomized to have multifocal or monofocal IOL implantation. Fifty-three eyes of 35 patients received a multifocal IOL and 67 eyes of 40 patients, a monofocal IOL. The incidence of complications and visual outcome in the multifocal and monofocal IOL groups were compared. Quality of vision was measured by comparing the severity of visual symptoms (glare, halos, and cataract symptoms score), changes in functional impairment measured by a 7-item visual function test (VF-7), changes in global measures of vision (trouble and satisfaction with vision), and range of accommodation and contrast sensitivity. RESULTS: Intraoperative and postoperative complications and adverse events were few and required no further surgical intervention. Both distance and near visual acuities were significantly better in the multifocal group than in the monofocal group; the difference was most prominent in distance corrected near acuity (P<.001). Thirty-five eyes (67.3%) in the multifocal group and 10 eyes (14.9%) in the monofocal group achieved a distance corrected near acuity of J6 (20/40) or better; 30 eyes (56.6%) and 19 eyes (28.4%), respectively, achieved a best corrected distance acuity of 20/20 or better. Glare symptoms decreased postoperatively in both groups but were slightly more common in the multifocal group. In contrast, halos were significantly more common at 1 month in the multifocal group (P<.001). Contrast sensitivity values were slightly lower with multifocal IOLs at almost all spatial frequencies, but the difference was not significant. The change in the quality of life postoperatively, measured with the VF-7, was significant and identical in both groups. CONCLUSIONS: Pseudophakic eyes with multifocal IOLs had better distance and near acuity and range of accommodation than eyes with a monofocal IOL. Slightly lower contrast sensitivity and increased perception of halos by subjects with the multifocal IOL appear to be an acceptable compromise to enhanced near and distance vision.     

Comparative analysis of visual quality between unilateral implantation of a trifocal intraocular lens and a rotationally asymmetric refractive multifocal intraocular lens

AIM: To compare visual quality after unilateral cataract surgery with implantation of trifocal intraocular lens (IOL) and asymmetric refractive multifocal IOL. METHODS: The prospective nonrandom, comparative study consisted of 60 eyes of 60 patients suffering unilateral cataract surgery with implantation of two different IOLs: AT LISA tri 839MP (30 eyes; Carl Zeiss Meditec, Germany) and LS-313 MF30 (30 eyes; Oculentis GmbH, Germany). Visual acuity, refractive outcome, contrast sensitivity, defocus curves, quality of vision, and optical phenomena were evaluated at 3mo postoperatively. RESULTS: There were no statistical differences between groups in uncorrected distance visual acuity (P=0.13) and uncorrected near visual acuity (P=0.54). In contrast, uncorrected intermediate visual acuity was better in trifocal group compared to the refractive multifocal group (P=0.02). No significant statistical between-group difference was detected in cylinder (P=0.43). Compared to trifocal group, spherical refraction and spherical equivalent in refractive multi focal group were more myopic (P<0.01). Under photopic conditions, no significant statistical differences were found between groups in contrast sensitivity at 3 and 6 cycles per degree (cpd). The refractive multifocal group performed better at 12 and 18 cpd than the trifocal group (P=0.01, P=0.034, respectively). The questionnaires of quality of vision and optical phenomena showed no differences between groups. CONCLUSION: Trifocal IOL is superior to refractive multifocal IOL in intermediate visual acuity. Rotationally asymmetric refractive multifocal IOL is more myopic in automated refraction and significantly better for the photopic contrast sensitivity at high frequency.     

Intraocular Lens Multifocality Combined with the Compensation for Corneal Spherical Aberration: A New Concept of Presbyopia-Correcting Intraocular Lens

The outcomes of a prospective consecutive study aimed at evaluating the visual and refractive benefit after cataract surgery with the implantation of the aspheric diffractive multifocal intraocular lens (IOL) Tecnis ZMB00 (Abbott Medical Optics) are reported. A total of 31 eyes of 19 patients (age range, 40 to 81 years) underwent phacoemulsification surgery with implantation of this aspheric multifocal IOL. At 6 months after surgery, postoperative spherical equivalent was within ±1.00 D in 96.8% of eyes, with 94.7% of patients presenting a postoperative binocular far LogMAR uncorrected visual acuity (UCVA) of 0.1 or better. Far best-corrected distance VA improved significantly (p < 0.01), with postoperative values of 0.1 or better in 96.8% of eyes. Postoperative near UCVA was 0.10 (equivalent to J1) or better in 93.55% of eyes. Furthermore, the IOL power was found to be very poorly correlated with the postoperative far LogMAR (r = 0.13) and near UCVA (r = 0.13). In conclusion, the aspheric diffractive multifocal IOL Tecnis ZMB00 provides a restoration of the far and near visual function after phacoemulsification surgery for cataract removal or presbyopia correction, which is predictable and independent from the optical power of the implanted IOL.Key words: Diffractive intraocular lens, Multifocal intraocular lens, Tecnis, Spherical aberration     

Refractive lens exchange versus iris-claw Artisan phakic intraocular lens for hyperopia

PURPOSE: To study a paired-match comparison between refractive lens exchange with pseudophakic IOL implant (RLE) and Artisan phakic IOL for high hyperopia. METHODS: Nineteen eyes (12 patients, 20 to 41 years old) with an Artisan phakic IOL (Model 203: 1.00-D increment) for hyperopia from +2.75 to +9.25 D were matched to 19 eyes (15 patients, 26 to 46 yr) with hyperopia from +2.75 to +7.50 D, who had refractive lens exchange (pseudophakic IOL implantation; lenses: 0.50-D increment). Average paired-match difference was 1.13 D and 7.7 years of age. RESULTS: At 1 month after surgery, 84% of refractive lens exchange/pseudophakic IOL eyes and 94% of Artisan phakic IOL eyes had a spherical equivalent refraction within +/- 1.00 D of emmetropia; 58% and 68% of eyes, respectively, were within +/- 0.50 D (P = .97). No eye lost lines of best spectacle-corrected visual acuity (BSCVA) and no significant changes in BSCVA were found in any eye at 1 month after surgery (P = .17). The percentage of eyes with uncorrected visual acuity (UCVA) of 20/40 or better improved from 79% to 89% of eyes at 1 to 2 months after phakic IOL; it remained at 89% to 82% of eyes from 1 to 2 months after refractive lens exchange/ pseudophakic IOL. The coefficient of correlation showed statistically better accuracy (intended vs. achieved refraction; P = .035) for the Artisan phakic IOL (R = 0.83) than for refractive lens exchange/ pseudophakic IOL (R = 0.50). CONCLUSIONS: Spherical equivalent refraction outcome and BSCVA after surgery were similar for both procedures. The Artisan phakic IOL in carefully selected patients provided a better overall outcome for young patients with high hyperopia whose accommodation was preserved, as compared to refractive lens exchange.     

Initial experience with a refractive multifocal intraocular lens in a Japanese population

PURPOSE: To evaluate a poly(methyl methacrylate) refractive, zonal-progressive multifocal intraocular lens (IOL) in patients requiring cataract surgery. SETTING: Department of Ophthalmology, Saiseikai Kurihashi Hospital, Saitama, Japan. METHODS: This open-label noncomparative study evaluated 58 eyes of 31 Japanese patients who had cataract surgery and implantation of a multifocal IOL (Array(R) PA154N, Allergan Surgical). The main outcome measures were visual acuity (VA) (distance and near, with and without correction), glare disability, and contrast sensitivity (CS) (distance and near, with and without glare under day and night conditions). A questionnaire was used to evaluate the effectiveness of the multifocal IOL. RESULTS: Uncorrected distance VA was 0.7 or better (20/30) in 56 eyes (97.0%) and uncorrected near VA, 0.5 or better (20/40) in 52 eyes (89.7%). Corrected distance VA was 0.7 or better in all eyes. Near VA with distance correction was 0.5 or better in 51 eyes (87.9%). Daytime CS was within the normal range. However, nighttime CS with central glare for both distance and near was markedly decreased. Under all conditions, distance CS was significantly better than near CS from middle- to high-frequency areas. Seventy-four percent of patients with the IOL in both eyes did not need glasses for daily activities, and the others needed glasses only to read for long periods. CONCLUSIONS: The results indicate that this refractive multifocal IOL is distance dominant and is beneficial in Japanese patients. However, since there are differences between Western countries and Japan in distance reading of characters and letters, further modification of this multifocal IOL may be required for use in Japanese patients.     

Intraocular lenses for the correction of refraction errors. Part II. Phakic posterior chamber lenses and refractive lens exchange with posterior chamber lens implantation

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.     

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.     

Functional outcomes after implantation of Tecnis ZM900 and Array SA40 multifocal intraocular lenses

PURPOSE: To evaluate the functional outcome after implantation of the Tecnis ZM900 multifocal intraocular lens (IOL) (AMO) and the Array SA40 multifocal IOL (AMO). SETTING: Department of Ophthalmology, Bundesknappschaft s Hospital, Sulzbach, and the Department of Ophthalmology, Marienhospital, Aachen, Germany. METHODS: In a prospective comparative 2-center trial, Tecnis ZM900 and the Array SA40 multifocal IOLs were bilaterally implanted in 50 patients (50 eyes Tecnis, 50 eyes Array) by 1 surgeon at each center. The following parameters were assessed 30 to 60 days and 120 to 180 days after surgery in both eyes: refraction, pupil size, uncorrected and best corrected visual acuities for distance and near at different contrast levels, and photopic and mesopic contrast sensitivity at different spatial frequencies. Patient satisfaction (spectacle independence, photic phenomena, overall satisfaction) was assessed by a questionnaire. RESULTS: The main differences between the 2 multifocal IOLs were the better uncorrected near visual acuity (P<.001), distance-corrected near visual acuity (P<.001), the mesopic contrast sensitivity at high spatial frequencies (P<.05) as well as greater independence from spectacles in patients with the Tecnis multifocal IOL, resulting in higher levels of patient satisfaction. CONCLUSION: The aspherical diffractive Tecnis multifocal IOL gave better outcomes than the Array multifocal IOL.     

Visual function with bilateral implantation of monofocal and multifocal intraocular lenses: a prospective, randomized, controlled clinical trial

PURPOSE: To evaluate visual function of three types of multifocal intraocular lenses (IOLs) and one monofocal IOL (as the control group) after cataract surgery. METHODS: One hundred fourteen patients participated in a prospective, randomized, controlled clinical study and received monofocal Tecnis Z9000 (AMO) (n = 24, 48 eyes); symmetric diffractive multifocal Tecnis ZM900 (AMO) (n = 26, 52 eyes); zonal refractive multifocal ReZoom (AMO) (n = 32, 64 eyes); and asymmetric diffractive multifocal TwinSet (Acri.Tec) (n = 32, 64 eyes) IOLs. RESULTS: Mean binocular distance best spectacle-corrected visual acuity (BSCVA) (logMAR) was 0.05 for controls, 0.08 for ZM900, 0.07 for ReZoom, and 0.11 for TwinSet, with mean binocular distance BSCVA at near of 0.49, 0.06, 0.22, and 0.11, respectively. Mean contrast sensitivity was better for the monofocal IOL group than for the multifocal IOLs. Patients assigned to TwinSet had less favorable contrast sensitivity scores. Patients with monofocal IOLs had more frequently recommended near addition (74%) than those with multifocal IOLs. Patients with refractive ReZoom had also recommended near addition more frequently than the two diffractive groups. The percentage of dysphotopsia phenomena was 81% in patients with diffractive multifocal ZM900 compared with 48% in patients with monofocal IOLs, 53% with refractive ReZoom, and 47% with diffractive TwinSet. CONCLUSIONS: The monofocal IOL showed better visual function and lesser photic phenomena than multifocal IOLs but patients were spectacle dependent. ReZoom provided better distance BSCVA than the TwinSet diffractive model. Patients with Tecnis and TwinSet diffractive multifocal IOLs were more spectacle independent than patients with ReZoom. Patients with TwinSet had the worst visual function. Patients implanted with the Tecnis diffractive ZM900 were those reporting more photic phenomena.     

A survey of intraocular lens explantation: a retrospective analysis of 23 IOLs explanted during 2005

PURPOSE: To evaluate the indications, lens styles, perioperative findings, and results of intraocular lens (IOL) explantation or exchange performed in the authors department in 2005. METHODS: The retrospective analysis comprised 22 patients (23 eyes). Twenty-one eyes had previous phacoemulsification and IOL implantation, one eye secondary aphakic IOL, and one eye phakic IOL implantation. The indications for IOL explantation/exchange and perioperative complications were evaluated. The best-corrected visual acuity (BCVA) before and after surgery was compared. RESULTS: Time from initial surgery to explantation/exchange varied from 1 to 121 months, median value was 46 months. The IOLs were explanted using local anesthesia and in 21 eyes replaced with new lens. Indications for IOL removal were opacification of the IOL in 12 eyes, malposition of the IOL in 5 eyes, postoperative refractive error in 2 eyes, recurrent toxic anterior segment syndrome in 1 eye, pseudophakic dysphotopsia in 1 eye, endothelial cell loss in phakic anterior chamber IOL in 1 eye, and visual discomfort with intraocular telescopic lens in 1 eye. The mean BCVA (decimal scale) before and after IOL explantation/exchange was 0.562+/-0.279 and 0.627+/-0.276, respectively. There was no significant difference in visual acuity before and after IOL exchange (Wilcoxon test). CONCLUSIONS: The most frequent indications for IOL explantation/exchange were opacification of the IOL and IOL malposition. Surgeries were uneventful in most cases. Final visual results have been largely good. Long-term follow-up of patients with various types of IOLs should be maintained.     

Prospective randomised double-masked trial of bilateral multifocal,bifocal or monofocal intraocular lenses

AIMS: To evaluate the functional effect of bilateral implantation of two different multifocal intraocular lenses (IOL) compared with the standard monofocal IOL. METHODS: Sixty-nine patients were recruited into a prospective, double-masked, randomised, controlled trial at a single hospital in the United Kingdom. Sixty completed follow-up; 16 implanted with monofocal IOLs, 29 with AMO 'ARRAY' multifocal IOLs and 15 with Storz 'TRUEVISTA' bifocal IOLs. Phacoemulsification and IOL implantation was performed to a standardised technique in both eyes within a 2-month period. The main outcome measures were distance and near visual acuity, depth of field and validated assessment of subjective function (TyPE questionnaire). RESULTS: naided distance acuity was good, and equivalent across the three groups. Corrected distance acuity was significantly lower in the bifocal group. Patients with multifocal and bifocal IOLs could read smaller absolute print size than those in the monofocal group (P = 0.05), but at a closer reading distance such that mean unaided near acuity was equal in the three groups. Corrected near acuity was significantly higher in the monofocal control group (P < 0.05). Depth of field was increased in multifocal (P = 0.06) and bifocal (P = 0.004) groups. Overall visual satisfaction was equal in the three groups, while near visual satisfaction was higher in the multifocal group than the monofocal (P = 0.04). Spectacle independence was not seen in the monofocal group, but was achieved in 28% of multifocal IOL patients and 33% of bifocal patients (P < 0.001). Adverse symptoms such as glare and haloes were significantly more bothersome with multifocal (not bifocal) IOLs than monofocals (P = 0.01). CONCLUSIONS: Multifocal and bifocal IOLs improved unaided near vision performance, with around one in three patients becoming spectacle-independent. The main adverse effect was an increased incidence of subjective glare and haloes in the multifocal IOL group.     

Visual results following implantation of a refractive multifocal IOL in one eye and a diffractive multifocal IOL in the contralateral eye

PURPOSE: To assess binocular visual results in patients who were scheduled to undergo cataract/refractive lens exchange with multifocal IOL implantation using a "mix & match" approach. METHODS: This prospective study enrolled 40 eyes of 20 patients aged between 44 and 78 years (median age = 58.1 years) implanted with a refractive multifocal IOL (ReZoom) in their dominant eye and a diffractive multifocal IOL (Tecnis) in their non-dominant eye. Near, intermediate, and distance vision were assessed at 2 months following implantation. Patients underwent refractive lens exchange or cataract surgery in the dominant eye first, followed by the non-dominant eye 1 to 2 weeks later. Emmetropia was the goal for all surgeries. RESULTS: Preoperatively, the mean spherical equivalent refraction was +2.019 +/- 1.417 diopters (D) (median: +2.063 D). The mean binocular distance decimal visual acuity was 1.06 +/- 0.60 D, the mean binocular intermediate decimal visual acuity was 0.50 +/- 0.90 D, and the mean binocular near decimal visual acuity was 1.10 +/- 0.40 D. CONCLUSIONS: Preliminary visual outcomes in this series of patients indicate good results at all distances.     

Refractive outcomes after bilateral multifocal intraocular lens implantation

PURPOSE: To evaluate the efficacy and safety of bilateral multifocal intraocular lens (IOL) implantation after cataract surgery. SETTING: Oftalmológico de Valencia-CEOVAL, Valencia, Venezuela. METHODS: This retrospective study evaluated patient charts for the patient selection method, preoperative evaluation, surgical technique, postoperative visual and refractive outcomes, and complications. It included 70 eyes of 35 patients who had lens extraction with bilateral implantation of an Array multifocal IOL. Fourteen eyes of 7 patients had hyperopia with presbyopia, and 56 eyes of 28 patients had cataract. RESULTS: All eyes achieved an uncorrected distance acuity of 20/40 or better and an uncorrected near acuity of J5 or better. Six patients (18%) reported moderate halos, and 22 patients (63%) occasionally wore glasses. CONCLUSION: Bilateral multifocal IOL implantation was effective and safe in cataract and hyperopic patients with presbyopia, providing good uncorrected distance and near acuities.     

Far and near visual acuity with multifocal intraocular lenses in an optomechanical eye model with imaging capability

PURPOSE: To compare the quantitative and qualitative visual performances of different multifocal intraocular lenses (IOLs) in an experimental model of the human eye. SETTING: University Hospital San Raffaele, Milan, Italy. METHODS: Five multifocal IOLs and 1 monofocal IOL were implanted in an optomechanical eye model with imaging capability. The comparative optical characterization of the imaging performance included aberrometry, simulated visual acuity testing at variable contrast for far and near distance, glare tests, and image records of optotype charts. RESULTS: The maximum recorded far visual acuity for the monofocal IOL was between 20/12.5 and 20/16; the multifocal IOLs decreased visual acuity by 1 to 2 lines. The difference tended to increase at reduced contrast. Full-contrast near visual acuity with multifocal IOLs ranged between 20/63 and 20/25; the near distance performance of the monofocal IOL without an additional correcting lens was worse by 1 to 3 lines of acuity with large pupils but was comparable with small pupils. Multifocal IOLs of different designs showed marked differences as a function of contrast, which tended to balance between far and near behaviors. CONCLUSIONS: Multifocal IOLs of different optical designs were well characterized and distinguished by simulated contrast acuity testing in an experimental eye model, allowing quantitative comparison. Their overall visual performance, averaged over contrast and distance, was not superior to the performance of a monofocal IOL without an additional correcting lens.