Three-piece Intraocular Lens Research Articles

Transscleral Fixation by Injector Implantation of a Foldable Intraocular Lens

Scleral fixation of a foldable intraocular lens (IOL) was performed in 17 eyes of 17 patients using a new small incision technique with injector implantation. All eyes were implanted with a hydrophobic acrylic three-piece IOL, either with phacoemulsification surgery or secondarily. No cases of intraoperative or postoperative complications were observed. The operation time required for scleral fixation only was less than 30 minutes in all cases. Scleral fixation of foldable IOLs using a self-sealing tunnel incision and injector technique minimizes intraoperative hypotony and related complications such as suprachoroidal hemorrhage. Furthermore, this technique saves surgery time and the sutureless technique used for most patients can reduce postoperative astigmatism.

Posterior capsular opacification after AcrySof one-piece vs three-piece intraocular lens implantation in pediatric cataract patients

Introduction: To compare the incidence of posterior capsular opacification (PCO) and secondary membrane (SM) after cataract extraction/IOL implantation (CE/IOL) with the AcrySof (Alcon) one-piece (SN60AT) vs three-piece (MA60AC) intraocular lens (IOL) in pediatric patients with or without primary posterior capsulotomy (PPC).

Posterior Capsule Opacification in Silicone and Hydrophobic Acrylic Intraocular Lenses with Sharp-edge Optics Six Years After Surgery

To compare posterior capsule opacification (PCO) between 2 three-piece intraocular lenses (IOLs) both with sharp-optic edges and open loop haptics, one made of silicone and the other made of hydrophobic acrylate, 6 years after surgery. Randomized, controlled, patient- and examiner-masked trial with intra-patient comparison. One hundred and six eyes in 53 patients were included initially. Forty-four eyes of 22 patients with age-related bilateral cataract were available for the 6 years follow-up. Each patient had standard cataract surgery and randomly received a silicone (CeeOn 911A; AMO, Santa Ana, California, USA) or hydrophobic acrylic (AcrySof MA60BM; Alcon, Fort Worth, Texas, USA) IOL in the first eye, the other type of IOL in the fellow eye. Follow-up examinations were at 1, 3, and 6 years after surgery. The intensity of posterior capsule opacification (PCO) was assessed using digital retro-illuminated photos and the "automated quantification of after-cataract" (AQUA) software. Neodymium-yttrium-aluminum-garnet-laser capsulotomies (YAG-LC) performed were noted. Six years after surgery, the AQUA scores were 2.3 +/- 1.4 for the silicone and 3.8 +/- 2.0 for the acrylic IOLs (P = .0016). The acrylic IOL eyes also had a significant increase in AQUA score from the 3-year to the 6-year follow-up. YAG-LC were performed in 2 silicone and 6 acrylic IOLs (P = .01). An angulated three-piece hydrophobic acrylic IOL had more PCO 6 years after surgery than a silicone IOL of otherwise similar design. Apart from an optic material effect, differences in haptic design and the degree of optic edge sharpness may play a role.

Mini- and Micro-incision Cataract Surgery – A Critical Review of Current Technologies

Modern cataract surgery is striving for smaller and smaller incisions with the aim of making clear corneal incisions that are as safe and topographically stable as possible. Recent innovations in both phacoemulsification (phaco) and intraocular lens (IOL) technology have made micro-incision cataract surgery, defined as <2mm incision, safe and effective. Bi-axial sleeveless micro-phaco has recently been joined by sleeve-armed micro-co-axial micro-phaco, made possible by the development of slim-shaft strong-bevel phaco needles armed with micro-sleeves that run flush with an enlarged needle head. Such tip technology allows for a highly efficient and safe high-flow, high-vacuum phaco through incisions as small as 1.4mm by providing high influx and suppressing surge while avoiding mechanical and thermal tissue damage. Two tips have so far been made available for mini- (2.2–2.4mm) and micro-incision cataract surgery (MICS) (1.4–1.6mm, depending on the incision architecture used). With the micro-tip supplemented by additional flow through an infusion spatula (‘infusion-assisted’ or ‘hybrid’ phaco), excessive flow and vacuum rates may be used, resulting in a two-fold efficiency as mirrored by the reduced phaco power required. IOL technology is lagging behind phaco technology. The challenge is to avoid trade-offs with regard to implant stability and aftercataract formation, as well as optical performance. Current MICS-IOLs are mostly hydrophilic acrylic one-piece constructions with insufficiently sharp posterior optic edges and broad haptic–optic junctions, both of which features compromise the optic-edge barrier effect. Recently, a hydrophobic three-piece IOL has been made available, which features a slim haptic junction and an exquisitely sharp optic edge and also allows for optional optic entrapment into a posterior capsulorhexis for lasting eradication of after-cataracts.

Visual perception of luxated intraocular lens by the patient

We examined a patient with a luxation of an encapsulated intraocular lens (IOL) who clearly perceived and drew detailed images of the IOL. A 74-year-old woman underwent vitrectomy with phacoemulsification,...

Late Spontaneous Haptic Disinsertion From a Three-Piece Intraocular Lens

To report two cases of spontaneous, late-onset haptic disinsertion from a three-piece posterior chamber intraocular lens (IOL). Interventional case reports. Two eyes of two patients had uncomplicated phacoemulsification and presented 16 and 20 years after surgery with spontaneous, nontraumatic haptic disinsertion from a three-piece IOL. In one case, the disinserted haptic dislocated into the anterior chamber while the IOL optic-single haptic complex remained centered and supported within the capsular bag. Cystoid macular edema was present, but resolved after removal of the disinserted haptic. In the second case, the disinserted haptic remained within the capsular bag while the IOL optic dislocated into the anterior chamber. Removal of the IOL and exchange with a sulcus-fixated single piece IOL was required. Nontraumatic haptic disinsertion from a three-piece IOL is a rare long-term complication after phacoemulsification.

Identification of the source of permanent glare from a three-piece IOL

To identify the source of unwanted glare images from a three-piece intraocular lens (IOL) implant following cataract surgery. The IOL and posterior capsule were examined under mydriatic and nonmydriatic conditions using direct focal illumination from a slit lamp biomicroscope. Direct focal illumination was undertaken with both a narrow beam (0.1 mm in width) and small spot (0.1 mm in diameter) to identify the points at which the glare images were stimulated. While observing the location of the beam with the slit lamp biomicroscope, the patient indicated when the glare images were stimulated. The nasal haptic insertion into the optic was identified as the source of temporal line images arising from lights such as headlamps from oncoming cars and street lamps. The adjacent edge of the IOL was also identified as the likely source of additional cob web-like light rays. The haptic insertions in three-piece IOLs may, under certain conditions, interfere with light entering the pupil and produce extraneous images. Large mesopic pupils and decentred IOLs are conditions that increase the likelihood of unwanted glare images.

Characterizing reflections from intraocular lens implants.

To develop a test method for characterizing glare from intraocular lenses (IOLs) and to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. The method consists of directing a collimated Gaussian laser beam to various parts of the IOL to be tested in a water-filled model eye. Reflected images produced in the retinal plane are photographed with a digital camera. A test method was developed to characterize the source of glare images from IOLs. The test method developed was used to confirm a clinical finding that the haptic insertion in the optic of a three-piece IOL produces extraneous line images. The method developed can be used to characterize and pin point the source of extraneous glare images from intraocular lens implants. The haptic insertion in the optic of a three-piece IOL has been identified as a source of line images.

A comparison of accommodation amplitudes in pseudophakic eyes measured with three different methods

To compare the accommodative amplitudes with three different methods in pseudophakic eyes with different types of intraocular lenses (IOLs). Fifty-one pseudophakic eyes of 44 patients (age: 72.02+/-8.53 years) were studied. One of two different types of IOL were implanted (N=30, three-piece Alcon Acrysof MA60AC and N=21, one-piece Alcon Acrysof SA60AT) in-the-bag after standard phacoemulsification. The time of the examinations was 13.85+/-7.35 months postoperatively. We measured the amplitude of accommodation with three different methods: (1) subjective minus-lenses-to-blur method; (2) a new optical device (ACMaster, Carl Zeiss, Jena, Germany) using partial coherence interference (PCI) technique under physiological stimulus; and (3) objective anterior chamber depth measuring with a standard A-scan ultrasonic device (Ultrascan Imaging System, Alcon Laboratories, Forth Worth, TX, USA) before and after pharmacological relaxation of ciliary muscle. We measured -0.83+/-0.63 D amplitude of accommodation with subjective minus-lenses-to-blur method. The IOL position did not change significantly during physiological accommodation effort measured with PCI method (-0.026+/-0.134 mm). The change in the IOLs position between near fixating and after ciliary muscle relaxation was -0.18+/-0.28 mm measured with ultrasound. There were no significant differences between values of one-piece and three-piece IOL groups. The amplitude of accommodation measured by subjective and objective methods are different and are not comparable with each other. We did not observe any difference between values of examined two types of IOLs.

Effect of Optic Material and Haptic Design on Anterior Capsule Opacification and Capsulorrhexis Contraction

To examine the influence of optic material (silicone and hydrophobic acrylic) and haptic design (one-piece and three-piece open loop) of sharp optic edge intraocular lenses (IOL) on anterior capsule opacification (ACO) and capsulorrhexis contraction. Randomized, controlled, double-blind clinical trial with intraindividual comparison. This study was performed at the Department of Ophthalmology, Medical University of Vienna, Austria, and comprised 210 eyes of 105 patients with bilateral age-related cataract. In group 1 (n = 53 patients), a three-piece acrylic IOL was compared with a three-piece silicone IOL. In group 2 (n = 52 patients), the three-piece acrylic IOL was compared with the one-piece acrylic IOL. One year after the operation, standardized digital slit-lamp images of ACO were taken; 1 week and 1 year after the operation, digital retroillumination images were taken to assess capsulorrhexis size. The intensity of ACO was graded objectively (score, 0% to 100%), and the capsulorrhexis area (square millimeters) was determined objectively. One year after surgery, the mean ACO score was 21% for the acrylic and 20% for the silicone IOL (P = .4) in group 1 and 18% for both the three-piece and one-piece acrylic IOLs (P = .87) in group 2. Concerning the amount of capsulorrhexis contraction, there was no significant difference between the IOL types that were evaluated in this study (after Bonferroni-Holm correction, P > .05). In the hydrophobic sharp optic edge IOLs that were examined, neither the optic material nor the haptic design had an influence on the amount of ACO or capsulorrhexis contraction.

Posterior capsule opacification

This paper assesses the factors that contribute to the formation of an effective capsular bend as a deterrent to posterior capsule opacification. Its goal is to assist the practicing ophthalmologist in separating current understanding of this process from various working models previously proposed. While a square-edge design appreciably improves resistance to posterior capsule opacification, significant factors remain under the control of the surgeon. These factors combine to form the physical and psychological barrier of a capsular bend. Innovative digital imaging has shown lens epithelial cell migration, allowing for a more rapid assessment of posterior capsule opacification resistance. A three-piece intraocular lens allows for full 360 degree capsular bend formation surrounding the optic edge; some single-piece designs may inhibit capsular bend formation. Decreasing, but not eliminating, the surviving lens epithelial cell population may diminish capsular bend strength, which may decrease resistance to posterior capsule opacification in the face of a regenerating cortex. All demographic features of clear/refractive lens exchange suggest higher rates of posterior capsule opacification than with standard cataract surgery. The quality of capsular bend formation will determine how resistant an intraocular lens will be to posterior capsule opacification as a consequence of regenerating cortex. As refractive lens exchange and new accommodating intraocular lens designs become more popular, the problems of regenerating cortex will increase in magnitude.

Modified Peripheral Iris Fixation of a Foldable Intraocular Lens Following Phacoemulsification

In this report, we describe the case of an aphakic patient who underwent peripheral iris fixation of a foldable posterior chamber intraocular lens (IOL) in the absence of capsular support. The patient suffered from traumatic cataract with partial zonular dehiscence. He received phacoemulsification, and capsular rupture occurred subsequently. After complete anterior vitrectomy, the lens capsule disappeared completely. Six months later, secondary IOL implantation was performed. A clear corneal incision was made, and a paracentesis was created to insert a folded acrylic soft IOL and a temporary supporting device. The optic of a three-piece acrylic IOL was folded along the axis of the haptics, and both the haptics were bent and quickly maneuvered into the folded furrow of the optic. A bimanual unfolding maneuver created pupillary capture of the optic for stabilization and centration of the IOL, with the haptics expanding on the back surface of the iris, and the haptics were fixated to the peripheral iris with modified McCannel suturing. Fair visual outcome without complications was noted.

Evaluation of a human capsular bag model for secondary cataract determination after intraocular lens implantation

To investigate the effect of different intraocular lenses (IOLs) on lens epithelial cells (LECs) and on human capsular bags in vitro and to evaluate the transferability of this model to clinical situations. Sham cataract surgery, including IOL-into-the-bag implantation, was performed on 38 donor eyes after removal of the cornea. The capsular bag including the IOL was removed, pinned on a culture dish, covered with medium, and incubated. Two different IOLs were compared per pair of donor eyes. In each pair of donor eyes, the two different IOLs to be compared were implanted individually into capsular bags. The time required for complete coverage of the posterior capsule by a confluent monolayer of LECs was documented. The following IOLs were compared: three-piece acrylic IOLs of different sizes and single-piece polymethylmethacrylate (PMMA) versus acrylic IOLs. A complete monolayer of LECs on the posterior capsule was observed to form at times varying from 8 days (PMMA IOLs) to more than 60 days (three-piece hydrophobic acrylic IOLs). A significant difference between PMMA IOLs and hydrophobic acrylic IOLs was found. The human capsular bag model employed allows short-term evaluation of secondary cataract formation for different IOLs. This model's correlation with clinical results is good.

The Effects of Three-Piece or Single-Piece Acrylic Intraocular Lens Implantation on Posterior Capsule Opacification

Purpose To evaluate the development of posterior capsule opacification (PCO) in patients implanted with 5.5 mm optics, single-piece or three-piece acrylic intraocular lens (IOL) in cataract surgery prospectively. Methods This study was carried out on 267 eyes of 249 patients implanted with three-piece, 5.5 mm optics, acrylic IOL and 252 eyes of 244 patients implanted with single-piece, 5.5 mm optics, acrylic IOL by phacoemulsification technique between September 2001 and February 2003. A total of 519 eyes of 493 patients were prospectively evaluated for PCO development during the 25-month period. All the patients were analyzed periodically with anterior segment retroillumination photography. The data provided were analyzed with chi-square method. Results The results between the two groups for PCO development were not statistically significant. However, there was a prominent opacification of the posterior capsule where the optic and haptic junction of IOL was positioned in some patients implanted with single-piece IOL. During the follow-up period, no patients implanted with either three-piece or single-piece acrylic IOL required Nd:YAG laser capsulotomy. Conclusions Biocompatibility and reduced rate of PCO development are among the leading features of new generation IOLs. The intracapsular implantation of 5.5 mm optics acrylic IOLs resulted in decreased incidence of PCO and therefore greater patient satisfaction. Further studies investigating the effects of IOL optics, haptic structure and length, capsulorrhexis size, and IOL material and design features on PCO development will clarify the subject.

Snowflake degeneration of polymethyl methacrylate posterior chamber intraocular lens optic material: A newly described clinical condition caused by unexpected late opacification of polymethyl methacrylate

Objective To report 25 cases of gradual, but sometimes progressive, late-postoperative degeneration of polymethyl methacrylate (PMMA) optics of posterior chamber (PC) intraocular lens (IOL) implants, often resulting in a clinically significant visual decrease long after the implantation, sometimes to a severity that required IOL explantation/exchange. Design Analysis of explanted PC IOLs, clinical histories, and photographs. Participants We analyzed 25 case histories/photographs and/or explants from 18 patients implanted in the 1980s to mid-1990s with three-piece PC IOLs with PMMA optics and with polypropylene or PMMA haptics. The IOL optic from each case had characteristic snowflake or crystalline opacifications. This condition occurred with more than one manufacturer and in some cases was restricted to certain lot numbers. Methods The explanted IOLs (n = 10) were studied by gross inspection and by light and scanning electron microscopy, as well as confocal and energy dispersive spectroscopy. Main outcome measures The snowflake lesions were noted within the IOL optics. The nature of these lesions was investigated. Results Assimilation of clinical information with pathologic and morphologic profiles of all cases suggested that the snowflake opacification was a small spherical lesion surrounded by an outer pseudocapsule composed of compressed, degenerated PMMA, with a central core containing convoluted fragments of PMMA. The lesions were classified into four clinical and pathologic grades according to their density and severity. Conclusions This is the first clinicopathologic correlative report on this complication. We postulate that manufacturing variations in some IOL models fabricated in the 1980s and early 1990s are responsible. The snowflake lesions seem to represent a destruction of the PMMA material. The cluster of lesions in implanted lenses manufactured by Surgidev was less progressive than some other models, including lenses made by IOPTEX Research Corporation. This identification of a condition previously unreported is important to alert clinicians regarding these perplexing lesions that may otherwise be considered idiopathic, with no obvious clinical hint as to their origin. The prevalence noted thus far is still too low to in any way suggest that this condition would occur in 100% of PMMA IOLs from these manufacturers. However, these late-occurring lesions, present in lens models that were implanted in hundreds of thousands of patients in the last decade or so, could have constituted a true epidemic, except that many of the patients are now deceased.

Change in capsulorhexis size with four foldable loop-haptic lenses over 6 months

Purpose: To compare the change in continuous curvilinear capsulorhexis (CCC) size after implantation of four types of three-piece foldable intraocular lenses (IOLs) and determine whether initial CCC size and IOL characteristics play a role in the change.Methods: This study comprised 133 eyes that had phacoemulsification and in-thebag implantation of one of four types of foldable IOLs: Alcon AcrySof™ MA30BA (n = 36); lovision™ 127 (n = 29); Mentor ORC MemoryLens™ (n = 39); Allergan PhacoFlex II™ (n = 29). Photographs of the CCCs were taken with a digital retinograph 1 day and 6 months after surgery. Using image-analysis software, the CCC surface was measured and changes between 1 week and 6 months were evaluated. Characteristics of the IOLs including overall diameter, optic thickness, and haptic centrifugal force were measured with micrometric tools.Results: The median change in CCC surface size at 6 months was +5.5% in the lovision group, indicating a slight enlargement. This finding was significantly different from that in the other three IOL groups (P < .0001), which had a tendency toward CCC contraction. Median change in CCC size was −2.3% in the MemoryLens group, −2.8% in the AcrySof group, and −6% in the PhacoFlex group. The MemoryLens was the most predictive IOL, with the smallest standard deviation; it was the only group in which no patient developed CCC contraction of more than 10%. Although the lovision and PhacoFex IOLs have common physical characteristics except for optic thickness (lovision 30% thicker), the CCCs in the lovision group were significantly more stable (P < .0001). Results indicate that the high centrifugal haptic force associated with acrylate/methacrylate polymer optics of the AcrySof and MemoryLens IOLs may prevent CCC contraction of greater than 10% in 97.4% of cases.Conclusion: Although there were statistically significant differences, patients in all four three-piece foldable IOL groups had good CCC stability. However, the more stable and predictable CCCs were in the IOL groups that had the strongest centrifugal haptic force and an acrylate/methacrylate polymer optic (AcrySof and MemoryLens).

Incision Sizes for Foldable Intraocular Lenses

The purpose of the study is to determine the minimal incision sizes required for implantation of a variety of different foldable intraocular lenses (IOLs) and to evaluate the effect of incision size on tissue damage. Randomized experimental study. Sixty-nine fresh human cadaveric eyes: 15 (pilot study), 48 (main study), and 6 (scanning electron microscopy study). Implantation of foldable IOLs into cadaveric eyes. In 48 fresh human cadaveric eyes, limbal corneal tunnel incisions were made, and in a randomized fashion, 8 different foldable IOLs of 20.5 diopters (D) were inserted: 4 silicone (SI-30NB, Allergan Medical Optics, Irvine, CA; C10UB, Chiron Ophthalmics, Inc, Irvine, CA; LI41U, IOLAB, Chiron Ophthalmics, Inc, Irvine, CA; AA-4203, Staar Surgical Company, Monrovia, CA); two soft acrylic (MA60BM and MA30BA, both Alcon Laboratories, Inc, Ft. Worth, TX); and two hydrogel models (SH30BC, Alcon; H60M, Storz Ophthalmics, Inc, St. Louis, MO). For each IOL model, six insertions were performed with a recommended implantation device. Using calipers, the authors measured internal and external incision sizes before and after insertion. Scanning electron microscopy was performed on selected incisions in six additional human cadaveric eyes. Incision sizes after insertion ranged from 3.2 to 3.8 mm. The smallest incisions permitting IOL insertion were associated with the injectors. However, these incisions enlarged after insertion by approximately 11% and then were similar to the incision sizes after forceps insertion of the high-refractive-index silicone, the 5.5-mm optic acrylic, and the one-piece hydrogel IOL. The largest incisions were associated with the 6-mm acrylic IOL and the three-piece silicone IOL with a lower refractive index. The scanning electron microscopy showed tearing of corneal tissue after implantation through the smallest incision; this was more pronounced with injectors than with forceps. Corneal tunnel incisions enlarged up to 11% after insertion of foldable IOLs through the smallest possible incision. With current technology, the smallest postinsertion incision size of a 20.5-D foldable IOL is 3.2 mm.

Decentration and Tilt of Polymethyl Methacrylate, Silicone, and Acrylic Soft Intraocular Lenses

Purpose: The purpose of the study is to investigate the periodic changes regarding the decentration and tilt of the intraocular lens (IOL) and to compare any differences in the decentration and tilt among polymethyl methacrylate (PMMA), silicone, and acrylic soft IOLs.Methods: A total of 225 cataractous eyes undergoing IOL implant surgery were randomized into 3 groups based on the type of IOL: group A, one-piece PMMA IOL; group B, three-piece silicone IOL; and group C, three-piece acrylic soft IOL. Both the length of the decentration and the degree of the tilt of the IOL were quantitated using the Anterior Eye Segment Analysis System (EAS-1000). All eyes underwent EAS-1000 examinations at 1 week as well as 1, 3, 6, 9, and 12 months after surgery.Results: All IOLs were confirmed to be implanted accurately in the capsular bag after continuous curvilinear capsulorhexis was accomplished. No statistically significant differences were observed regarding the IOL decentration or tilt between the various postoperative periods in any of the three IOL groups. Furthermore, the differences regarding both the IOL decentration and the tilt between the three IOLs were not determined to be statistically significant throughout the observation period.Conclusions: As long as the IOL was placed properly in the capsular bag after the continuous capsulorhexis, neither the decentration nor the tilt of the IOL showed a significant progression up to 12 months after surgery. Furthermore, both the extent of the decentration and tilt almost were the same among the PMMA, silicone, and acrylic soft IOLs.

Enlargement of Incision Width during Phacoemulsification and Folded Intraocular Lens Implant Surgery

The authors investigated the dimensional stability of incisions during phacoemulsification and small-incision intraocular lens (IOL) implantation. Forty-six eyes undergoing temporal clear corneal phacoemulsification and folded silicone IOL implantation were measured with an internal-incision gauge after initial keratome entry, cataract removal, and folded IOL implantation. The initial incision created by a diamond keratome was wider than the physical keratome width by a mean of 0.16 mm. After completion of phacoemulsification and irrigation/aspiration, the incision further widened by a mean of 0.09 mm. Both forceps insertion of a three-piece silicone IOL and injector insertion of a plate haptic silicone IOL resulted in further incision enlargement by a mean of 0.26 mm. Widening the incision before IOL insertion did not eliminate even further incision expansion during the IOL insertion. The phacoemulsification incision enlarges at each step of the procedure. Irreversible incision stretching or incision tearing occurs, rather than reversible elastic incision deformation. Clinical studies that assume the initial keratome size equals the final incision size may be erroneous.

Centration and fixation of silicone intraocular lenses: Clinicopathological findings in human autopsy eyes

AbstractPurpose: To analyze centration and fixation of three-piece and one-piece silicone intraocular lenses (IOLs) in human autopsy eyes.Setting: Center for Intraocular Lens Research, Medical University of South Carolina, Charleston.Methods: Thirty eyes among those submitted to the center between 1986 and 1994 were evaluated. The globes were sectioned at the equatorial plane and photographed from a posterior view. Gross examination was performed to determine IOL type, fixation, centration, and additional pathology. The results were compared with those of a control group of autopsy eyes implanted with one-piece and three-piece poly(methyl methacrylate) (PMMA) IOLs. The control group matched the silicone group in patient age, fixation site, and duration of implantation.Results: Twenty-three eyes (79.3%) had three-piece silicone IOLs and 7 eyes (20.7%), one-piece plate IOLs. Average patient age in the three-piece group was 77.3 years ± 6.7 (SD) and in the one-piece group, 74.3 ± 3.8 years. The 30 IOLs were symmetrically fixated in the bag. Average decentration of the three-piece and one-piece IOLs did not differ significantly, 0.37 ± 0.31 mm and 0.26 ± 0.13 mm, respectively (P = .37). There was also no significant difference in decentration between the silicone groups and the PMMA groups (P = .93).Conclusion: Centration and fixation of silicone IOLs were equivalent to those of standard PMMA IOLs.