Effect of heparin surface modification in reducing silicone oil adherence to various intraocular lenses.

PURPOSE: To evaluate surface properties of various intraocular lenses (IOLs), including a newly fabricated heparin-surface-modified (HSM) silicone IOL, with special reference to their efficiency in reducing potential silicone oil adherence to the IOL optics. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Five groups of rigid and foldable IOLs were analyzed in an in vitro test for the percentage of silicone oil adherence: a single-piece foldable hydrophilic-acrylic IOL (n = 9); a single-piece rigid poly(methyl methacrylate) (PMMA) IOL with HSM coating of the lens optic (n = 9); a 3-piece foldable silicone optic IOL with HSM coating of the optic (n = 10); a single-piece standard rigid PMMA IOL (n = 7); and a standard 3-piece foldable silicone optic IOL (n = 9). After the IOLs were immersed in water and then in silicone oil, gross photographs taken. Image analysis was performed to evaluate the percentage of silicone oil coverage of the anterior and posterior surfaces of each IOL optic. RESULTS: The mean silicone oil coverage of the hydrophilic-acrylic IOLs was 5.6% +/- 2.5% (SD); of the HSM PMMA IOLs, 6.2% +/- 4.3%; of the HSM silicone optic IOLs, 6.7% +/- 3.2%; and of the standard PMMA IOLs, 20.3% +/- 13.3%. The mean silicone oil coverage was greatest on the standard silicone optic IOLs, 98.2% +/- 3.1%. CONCLUSIONS: Intraocular lenses with a hydrophilic optic have less tendency toward adherence to silicone oil than more hydrophobic designs. A foldable silicone IOL with heparin surface modification can significantly reduce potential silicone oil adherence, comparable to the level achievable with the rigid HSM PMMA designs. Two new foldable IOL styles, the HSM silicone IOL and IOLs in the general class of hydrophilic-acrylic, were highly efficacious in reducing silicone oil adherence. There is now a real choice of foldable lenses for patients with actual or potential vitreoretinal diseases.     

Interaction with intraocular lens materials: Does heavy silicone oil act like silicone oil?

PURPOSE: To determine the interaction of heavy silicone oil with various intraocular lens (IOL) materials and whether heavy silicone oil covers the silicone IOL optic as silicone oil does. SETTING: Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey. METHODS: The study group comprised 5 poly(methyl methacrylate) (PMMA) IOLs, 4 foldable silicone IOLs, 5 foldable hydrophilic acrylic IOLs, and 5 foldable hydrophobic acrylic IOLs. Each IOL was bathed in balanced salt solution (BSS) for 10 minutes and then placed in heavy silicone oil dyed with Sudan Black for another 10 minutes. Afterward, each IOL was reimmersed in BSS for 5 minutes and examined under the light microscope. Digital images were analyzed to determine the optic area covered with heavy silicone oil. RESULTS: The mean heavy silicone oil coverage was 7.05% +/- 7.88% (SD) (range 1.13% to 20.54%) on PMMA IOLs, 100% on silicone IOLs, 12.17% +/- 11.43% (range 1.25% to 31.52%) on hydrophobic acrylic IOLs, and 34.64% +/- 13.28% (range 12.57% to 44.42%) on hydrophilic acrylic IOLs. Heavy silicone oil coverage of silicone IOLs was statistically significantly greater than the coverage of other IOL materials. CONCLUSION: Heavy silicone oil acted the same as silicone oil and covered the entire surface of silicone IOLs.     

Adherence of triamcinolone acetonide to various intraocular lens materials

PURPOSE: To determine the adherence of triamcinolone acetonide to various intraocular lens (IOL) materials. SETTING: Department of Ophthalmology, Dokuz Eylül University, Izmir, Turkey. METHODS: Four IOLs of 4 materials (single-piece poly(methyl methacrylate) [PMMA], 3-piece foldable silicone, 3-piece hydrophobic acrylic, and single-piece hydrophilic acrylic) were first immersed in triamcinolone acetonide (40 mg/mL) for 15 minutes and then bathed in a balanced salt solution for another 15 minutes. Afterward, each lens optic was examined under light microscopy and digital images were obtained with a digital color video camera. The percentage of optic area covered with triamcinolone acetonide was determined by image analysis. RESULTS: Mean triamcinolone coverage was 7.62% +/- 4.06% (SD) for PMMA IOLs (range 1.97% to 11.43%), 9.09% +/- 4.60% for silicone IOLs (range 4.70% to 15.32%), 8.75 +/- 7.20% for hydrophobic acrylic IOLs (range 1.31% to 16.86%), and 23.16 +/- 8.53% for hydrophilic acrylic IOLs (range 15.02% to 35.12%). Adherence of triamcinolone acetonide to hydrophilic acrylic lenses was statistically significant when compared with other IOL materials. CONCLUSION: Intraoperative triamcinolone injection may obscure visualization intraoperatively and postoperatively, especially in eyes with hydrophilic acrylic lenses, because triamcinolone acetonide seems to have a tendency to adhere to hydrophilic acrylic lenses in vitro.     

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2003 survey update

The sixth annual survey of complications associated with foldable intraocular lenses (IOLs) requiring explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were evaluated. Complications were then tabulated for each of the following major foldable IOL groups: 3-piece monofocal silicone, 3-piece hydrophobic acrylic, 1-piece hydrophobic acrylic with haptics, 3-piece hydrophilic acrylic (hydrogel), 1-piece hydrophilic acrylic (hydrogel), 1-piece plate-type silicone, 3-piece multifocal silicone, and Collamer. Two hundred seventy-three surveys were returned for evaluation. Dislocation/decentration, incorrect lens power, IOL calcification, and glare/optical aberrations were the most common reasons for removing foldable IOLs. Good surgical technique, accurate IOL power measurements, and high manufacturing standards for foldable IOL materials and designs are the most important factors in avoiding complications with foldable IOLs.     

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2001 survey update

A survey of the complications associated with foldable intraocular lenses (IOLs) that required explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were assessed. Postoperative results and outcomes were also analyzed. Complications and symptoms for each of the following major groups of foldable IOLs explanted were tabulated separately: 3-piece hydrophilic acrylic or hydrogel; 3-piece monofocal silicone; 3-piece hydrophobic acrylic; 1-piece hydrophobic acrylic with haptics; 3-piece multifocal silicone; 1-piece plate-type silicone. A total of 286 surveys were returned for evaluation. Intraocular lens calcification, incorrect lens power, optical visual aberrations, and decentration/dislocation were the most common reasons for removing a foldable IOL. Accurate IOL measurements, meticulous surgical technique, proper patient counseling, and careful manufacture of foldable IOL materials are the most important factors in avoiding complications with foldable IOLs.     

Evaluation of 3 modern single-piece foldable intraocular lenses: clinicopathological study of posterior capsule opacification in a rabbit model

PURPOSE: To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering's ring formation were evaluated 3 weeks after surgery using the Miyake-Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry. RESULTS: The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P <.05). There was no significant difference in Soemmering's ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material. CONCLUSIONS: The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.     

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2007 survey update

The tenth annual survey of complications associated with foldable intraocular lenses (IOLs) requiring explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were evaluated. Complications were then tabulated for each of the following major foldable IOL groups: 1-piece (plate) silicone, 1-piece hydrophobic acrylic with haptics, 3-piece silicone, 3-piece hydrophobic acrylic, 3-piece hydrophilic acrylic (hydrogel), 3-piece unknown, multifocal acrylic, and multifocal silicone. One hundred forty-two surveys were returned for evaluation. Dislocation/decentration, incorrect IOL power, glare/optical aberrations, and IOL calcification were the most common reasons for removing foldable IOLs. Good surgical technique, accurate IOL power measurements, and high manufacturing standards for foldable IOL materials and designs are the most important factors in preventing complications.     

Complications with foldable intraocular lenses with subsequent explantation in 1998 and 1999. Results of a questionnaire evaluation

Purpose. A questionnaire was sent to all members of the German Society of Ophthalmic Surgeons to evaluate complications of foldable intraocular lenses (IOLs) that required explantation. Methods. Information on preoperative visual acuity, foldable IOL design and material as well as the reason for IOL explantation was obtained and analysed. We received 167 completed questionnaires for 1998 and 1999. Results. In 1998 and 1999 the most common reasons for IOL explantation were as follows: incorrect lens power for 56% of the 3-piece hydrophobic acrylic IOLs, 16% because of glare or other photic phenomena, 40% of the 1-piece hydrophilic acrylic IOLs were explanted because of incorrect lens power and 30% for IOL damage. For the 3-piece monofocal silicone IOLs, 41% were explanted because of incorrect IOL power and 32% because of IOL decentration. For the 1-piece Hydrogel IOL, 76% were explanted because of opacification of the optic and 14% because of incorrect lens power. Most multifocal IOLs were explanted because of photic phenomena. Conclusion. In addition to the most common complications such as decentration and incorrect IOL power observed in rigid IOLs, new complications associated with foldable IOLs occurred such as optic opacification, glare and photic phenomena. Some complications seemed to appear in particular IOL types (opacification: SC-60BOUV, MDR), while others were observed in all types of foldable lenses. Accurate calculation of the IOL power and further improvement of the IOL material and design seem to be necessary to minimise the rate of explantations.     

Uveal and capsular biocompatibility of hydrophilic acrylic, hydrophobic acrylic, and silicone intraocular lenses.

PURPOSE: To evaluate the long-term response of 6 types of 3-piece intraocular lenses (IOLs) by assessing the cellular reaction on the anterior IOL surface, the behavior of posterior and anterior capsule fibrosis, and flare. SETTING: Department of Ophthalmology, Medical School, University of Vienna, Vienna, Austria. METHODS: One hundred eighty eyes were prospectively randomized to receive 1 of 6 IOLs: hydrophilic acrylic Hydroview (Bausch & Lomb) or MemoryLens (ORC); hydrophobic acrylic AcrySof MA60BM (Alcon) or AMO Sensar AR40 (Allergan); hydrophobic silicone CeeOn 920 or CeeOn 911A (Pharmacia). The patients had standardized cataract surgery, postoperative medication, and follow-up. One year after surgery, 155 eyes were assessed. The cellular reaction was evaluated by specular microscopy of the anterior IOL surface. Anterior and posterior capsule opacification (PCO) was assessed semiquantitatively by biomicroscopy. Flare was measured with a Kowa FC-1000 laser flare-cell meter. RESULTS: Regarding uveal biocompatibility, the hydrophobic acrylic IOLs showed the highest incidence of late foreign-body cell reaction (AcrySof, 30%; AR40, 17%) followed by the hydrophilic acrylic (MemoryLens, 8%; Hydroview, 4%) and silicone (CeeOn 920, 4%; CeeOn 911A, 0%) (P =.0044). In all cases, the cellular reaction was low grade and clinically insignificant. Regarding capsular biocompatibility, some eyes developed lens epithelial cell (LEC) outgrowth on the anterior IOL surface. The highest incidence was in the hydrophilic acrylic group (Hydroview, 85%; MemoryLens, 27%) followed by the hydrophobic acrylic (AcrySof, 4%; AR40, 3%). No silicone IOL had LECs on the anterior surface. The difference among IOL groups was significant (P =.0001). Anterior capsule opacification was more predominant in the hydrophobic IOL groups. Posterior capsule opacification of the central 3.0 mm area was lowest in the groups with a sharp-edged optic (CeeOn 911A, AcrySof) followed by the round-edged silicone (CeeOn 920), hydrophobic acrylic (AR40), and hydrophilic acrylic IOLs (P =.0001). There was a significant difference in flare between the AR40 lens and the Hydroview, MemoryLens, CeeOn 911A, and CeeOn 920 (P <.004). There was no statistically significant difference in the postoperative cell count at 1 year. The power calculation showed that the sample size was sufficient. CONCLUSIONS: The differences in cellular reaction, although clinically mild in normal eyes, indicate that there were more giant cells with hydrophobic acrylic IOLs and an increased tendency toward LEC outgrowth with hydrophilic lenses. The incidence of PCO was lowest in the hydrophobic IOL groups, especially in groups with a sharp-edged optic. Second-generation silicone IOLs with a sharp edge had good uveal and capsular biocompatibility 1 year after surgery.     

Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study

AIMS—To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule.
METHODS—Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically.
RESULTS—The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p=0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL.
CONCLUSIONS—The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.

Keywords: intraocular lens; lens capsule; posterior capsule opacification; adhesion     

Incision sizes with 5.5 mm total optic, 3-piece foldable intraocular lenses

PURPOSE: To determine incision sizes for 5.5 mm total optic, foldable intraocular lenses (IOLs) made of silicone or hydrophobic acrylic. SETTING: Johann Wolfgang Goethe-University, Department of Ophthalmology, Frankfurt am Main, Germany. METHODS: In a prospective randomized clinical study including 40 cataract procedures with a temporal limbal tunnel approach, incision sizes for 5.5 mm optic, 3-piece foldable IOLs were measured before and after phacoemulsification and before and after IOL implantation using calipers. Three 5.5 mm optic, 3-piece foldable IOLs were used: 2 silicone (Pharmacia CeeOn 912, Allergan SI-55NB) and 1 hydrophobic acrylic (Alcon AcrySof MA30BA). Ten lenses of each model were implanted with a forceps, and 10 SI-55NB IOLs were implanted with the AMO Unfolder injector. Measurements of the tunnel incisions at various times were statistically evaluated using an analysis of variance and the Tukey-Kramer multiple comparison test. RESULTS: Mean tunnel width before and after implantation, respectively, was 3.32 mm+/- 0.06 (SD) and 3.42+/- 0.06 mm for the CeeOn 912 using a Nichamin implantation forceps, 3.28+/- 0.09 mm and 3.42+/- 0.09 mm for the AcrySof MA30BA using a Buratto implantation forceps, 3.00+/- 0.07 mm and 3.10+/- 0.05 mm for the SI-55NB using a Fine Universal II Folder, and 2.66+/- 0.08 mm and 2.81+/- 0.11 mm for the SI-55NB using the AMO Unfolder. Incision sizes before and after implantation were statistically different between 2 IOLs (CeeOn 912 and MA30BA) and the SI-55NB groups. Implantation of the SI-55NB with the Unfolder was associated with significantly smaller incision sizes before and after implantation than implantation with the Fine folder. CONCLUSIONS: Incisions sizes of 2.8 to 3.4 mm were associated with 5.5 mm total optic, 3-piece foldable IOLs. The Allergan SI-55NB high-refractive-index silicone IOL implanted with the AMO Unfolder system provided the smallest postimplantation incision; however, the refractive optic of this IOL is 5.0 mm versus 5.5 mm for of the CeeOn 912 and AcrySof MA30BA.     

Complications of foldable intraocular lenses requiring explantation. Results of the 2000 and 2001 survey in Germany

PURPOSE. A survey was sent to all members of the German Society of Ophthalmic Surgeons to evaluate complications that required explantation of foldable intraocular lenses (IOLs). METHODS. Data on preoperative visual acuity, foldable IOL design and material, and the reason for explantation were obtained and analysed. We received 185 surveys for 2000 and 2001. RESULTS. In 2000 and 2001, the most common reasons for IOL explantation were: incorrect lens power (31%) and dislocation (19%) in three-piece acrylic IOLs, incorrect power (31%) and decentration (17%) in monofocal silicone IOLs, and opacification (46%) in hydrophilic IOLs. The most common reasons for the exchange of monofocal IOLs were lens opacification in 2000 and incorrect IOL power in 2001. CONCLUSION. Besides the most frequent complications of decentration and incorrect power observed in rigid IOLs,new complications associated with foldable IOLs occurred (e.g., optic opacification and calcification). Accurate calculation of IOL power and further improvements in material and design are still necessary to minimize the rate of explantations.     

Analysis of intraocular lens surface properties with atomic force microscopy

PURPOSE: To analyze the surface optics of 4 currently available intraocular lenses (IOLs) with atomic force microscopy. SETTING: Licryl Laboratory, University of Calabria, Rende, Italy. METHODS: The surface roughness and topography of poly(methyl methacrylate) (PMMA), silicone, hydrophobic, and hydrophilic acrylic IOLs were evaluated with atomic force microscopy in contact mode. The analysis was performed in a liquid environment using cantilevers with a 0.01 Newtonw/meter nominal elastic constant. Measurements were made over areas of 10 microm2 on different locations of the posterior optic surface of the IOL. RESULTS: Atomic force microscopy permitted high-resolution imaging of IOL optic surface characteristics. Surface topography showed different features with respect to the lens biomaterial. The root-mean-square roughness of the IOL optic surface was significantly different between lenses of various materials (P < .001). The hydrophobic acrylic and silicone IOLs had the lowest mean surface roughness, 3.8 nm +/- 0.2 (SD) and 4.0 +/- 0.5 nm, respectively, and the 2 PMMA IOLs had the highest mean surface roughness, 6.6 +/- 0.3 nm and 7.0 +/- 0.6 nm. CONCLUSIONS: Atomic force microscopy was effective and accurate in analyzing IOL optics. The surface topography of IOLs may vary with different manufacturing processes.     

Bacterial adhesion to rigid and foldable posterior chamber intraocular lenses: in vitro study

PURPOSE: To determine the in vitro bacterial adherence to intraocular lenses (IOLs) routinely used at 1 center. SETTING: University Hospital of Vienna, Vienna, Austria. METHODS: Four types of rigid IOLs (hydrophobic poly[methyl methacrylate] [PMMA] and hydrophilic heparin-surface-modified PMMA) and 5 types of foldable intraocular lenses (hydrophobic silicone, hydrophobic acrylic, and hydrophilic acrylic) were used in the experiment. Under standardized conditions, the IOLs were contaminated with 2 strains of Staphylococcus epidermidis. A sonication method and impression method were used for quantification. The mean bacterial density per lens type (colony forming units/mm(2)) was compared. RESULTS: With both germs and both quantification methods, more bacteria was found on hydrophobic lenses than on IOLs with hydrophilic surfaces (P =.001). The Alcon AcrySof and Askin UV80F IOLs had the greatest and the Corneal Acrygel and Bausch & Lomb Hydroview IOLs the least affinity to these microorganisms. CONCLUSION: The data suggest that hydrophilic IOLs can help reduce the rate of postoperative endophthalmitis as a result of their surface properties.     

Complications of foldable intraocular lenses requiring explanation or secondary intervention--1998 survey

A survey of the complications associated with foldable intraocular lenses (IOLs) that required explantation or secondary intervention was sent to domestic members of the American Society of Cataract and Refractive Surgery in 1998. Preoperative data as well as patient signs and symptoms were obtained and postoperative results and outcomes assessed. The types of foldable IOLs explanted were tabulated. The percentage of each type removed and the common reasons for removal were as follows: 38%--3-piece monofocal silicone IOLs for incorrect lens power followed by dislocation/decentration; 31%--3-piece multifocal silicone IOLs for glare/optical aberrations; 16%--3-piece acrylic IOLs for glare/optical aberrations followed by incorrect lens power and dislocation; 15%--1-piece or plate-haptic silicone IOLs for dislocation/decentration followed by incorrect lens power. Visual outcomes were uniformly good in the 4 groups. Meticulous surgical technique, IOL insertion, and IOL power measurements, along with proper patient selection, are important factors in avoiding complications with foldable IOLs.     

Incision width after phacoemulsification with foldable intraocular lens implantation

PURPOSE: To determine the incision size after insertion of foldable intraocular lenses (IOLs) using both a forceps and injectors. SETTING: Intermountain Ocular Research Center, Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: One hundred patients had phacoemulsification through a clear corneal wound. The incision width was measured before and after IOL implantation. A 3-piece silicone IOL and a 3-piece acrylic IOL (both with an optic diameter of 5.5 mm) were inserted using a forceps. A plate-haptic silicone lens and a 3-piece silicone lens with a 6.0 mm diameter optic were inserted using an injector. RESULTS: The wound size in the group with the 3-piece silicone lens inserted with a forceps enlarged 4.4% (3.23 to 3.38 mm) in the low-power IOL group (15.0 to 20.0 diopters [D]) and 6.2% (3.24 to 3.44 mm) in the high-power IOL group (20.5 to 25.0 D). Similarly, the acrylic IOL wound enlarged 5% (3.21 to 3.37 mm) in the low-power IOL group and 6% (3.25 to 3.44 mm) in the high-power IOL group when a forceps was used. The 3-piece silicone and plate silicone lenses inserted using an injector enlarged the wound 3.2% and 3.3% (3.02 to 3.11 mm and 3.05 to 3.15 mm), respectively. There was no difference in the wound size with higher IOL powers in eyes with injected lenses. CONCLUSIONS: Clear corneal incisions enlarge after insertion of foldable IOLs in a predictable manner, with a forceps-inserted IOL enlarging the wound diameter more than lenses inserted with an injector. The forceps-inserted lens group also showed a difference in wound size related to IOL power.     

Posterior capsule opacification after implantation of a hydrophilic or a hydrophobic acrylic intraocular lens: one-year follow-up

PURPOSE: To evaluate the effect of hydrophilic and hydrophobic single-piece acrylic intraocular lenses (IOLs) on posterior capsule opacification (PCO) after cataract surgery. SETTING: St. Erik's Eye Hospital, Stockholm, Sweden. METHODS: In a prospective study, 120 patients having cataract surgery were randomized to implantation of a hydrophilic acrylic IOL (BL27, Bausch & Lomb) or a hydrophobic acrylic IOL (AcrySof SA60AT, Alcon). Surgery was performed according to a standardized protocol by 1 of 3 surgeons. Best corrected visual acuity, contrast sensitivity, glare, intraocular pressure, and flare were measured 1 week, 3 months, and 1 year after surgery. Posterior capsule opacification was assessed by digital retroillumination photography and analysis using POCOman software at 1 year. The rate of neodymium:YAG (Nd:YAG) capsulotomy for each IOL was also recorded. RESULTS: At 1 year, the hydrophilic acrylic IOL group had a significantly greater percentage area and severity of PCO than the hydrophobic acrylic IOL group (P<.001). Two patients in the hydrophilic acrylic IOL group and 4 in the hydrophobic acrylic IOL group had an Nd:YAG capsulotomy within the first year (P>.05). Contrast sensitivity was significantly better in the hydrophilic acrylic group at 3 months (P<.05); however, at 12 months no difference between the IOLs was observed. There was no significant difference in the other measured parameters. CONCLUSION: Patients with the hydrophilic acrylic BL27 IOL had a significantly greater percentage area and severity of PCO than those with the hydrophobic acrylic SA60AT IOL 1 year after surgery.     

Tilt and decentration of three-piece foldable high-refractive silicone and hydrophobic acrylic intraocular lenses with 6-mm optics in an intraindividual comparison

PURPOSE: Intraindividual comparison of tilt and decentration of three-piece foldable intraocular lenses (IOLs) with 6-mm optics and different edge design and material. DESIGN: Prospective randomized study. METHODS: Twenty-five patients with senile cataract (group I) received a foldable silicone, sharp optic edge IOL in one eye and a silicone, rounded optic edge IOL in the other eye. Group II (n = 28) received the foldable silicone, sharp optic edge IOL in one eye and an acrylate, sharp optic edge IOL in the other eye. Scheimpflug photography was performed after the procedure with an anterior eye segment analysis system. Tilt and decentration of the IOL optic were measured 1 week, 6 months, and 12 months after the procedure. RESULTS: In group I, the foldable silicone, sharp optic edge IOL showed a mean optic tilt of 3.03 +/- 1.79 degrees and an optic decentration of 0.24 +/- 0.13 mm; the silicone, rounded optic edge IOL showed a tilt of 3.26 +/- 1.69 degrees and a decentration of 0.23 +/- 0.13 mm. In group II, the foldable silicone, sharp optic edge IOL showed an average tilt of 2.34 +/- 1.81 degrees and a decentration of 0.29 +/- 0.21 mm after 12 months; the acrylate, sharp optic edge IOL had a tilt of 2.32 +/- 1.41 degrees and a decentration of 0.24 +/- 0.10 mm. There were no significant differences in either group. CONCLUSION: The examined IOLs showed a stable position regarding tilt and decentration in the first 12 postoperative months, independent of material and edge design. Slight deviations from the optical axis might affect the outcome in aspheric or multifocal IOLs.     

Intraindividueller Vergleich von Intraokularlinsen aus hochrefraktivem Silikon (Allergan SI40NB) und hydrophobem Acrylat (Alcon Acrysof MA60BM) 1-Jahresergebnisse

Background. A prospective, randomized study was performed to evaluate intraindividually the biocompatibility of foldable, highly refractive silicone and hydrophobic acrylic intraocular lenses (IOL). Materials and methods. We studied 35 patients who underwent phacoemulsification using a self-sealing tunnel incision. In a randomized fashion one eye received a 6-mm optic IOL made of high-refractive index silicone (Allergan SI40NB) and the other eye a hydrophobic acrylic 6-mm optic IOL (Alcon AcrySof MA60BM). All patients were examined 7 days, 1–3 and 6 months, and 1 year postoperatively. Results. The mean best-corrected visual acuity (BCVA) was 0.9±0.12 vs. 0.89±0.13 (SI40NB vs. MA60BM) after 1–3 months. One-year postoperatively BCVA was still 0.9±0.12 vs. 0.87±0.14. The flare values (photon counts/ms) increased slightly 7 days after surgery (14.2±8.68 vs. 15.49±7.2, n.s.). Three months after surgery these values were again in the normal range. The mean IOL decentration was 0.29±0.14 vs. 0.3±0.15 mm 1 year postoperatively. Scheimpflug slit photography showed 40% of MA60BM IOLs to have “glistenings.” No significant difference regarding posterior capsular opacification was found. Conclusion. One year after implantation of foldable, highly refractive silicone and hydrophobic acrylic IOLs using a self-sealing tunnel incision and phacoemulsification, no significant functional or morphological differences between the two IOL types were observed.     

Differential responses of human lens epithelial cells to intraocular lenses in vitro: hydrophobic acrylic versus PMMA or silicone discs

Background The purpose of this study was to determine the influence of different materials of intraocular lenses (IOLs) on human lens epithelial cell behavior, including adhesion, migration, proliferation, apoptosis, and epithelial-mesenchymal transdifferentiation (EMT) in vitro. Methods Human lens epithelial cells (SRA 01/04) were grown on hydrophobic acrylic (Acrysof), polymethylmethacrylate (PMMA), and silicone IOLs. Cellular adhesion, migration, proliferation, and apoptotic assays were performed to assess cell behavior. The expression of EMT markers (fibronectin and type I collagen) produced by cells on IOLs was determined by immunoblotting and immunocytochemistry. Results Human lens epithelial cells exhibited preferred adhesion and reduced apoptosis when cultured on acrylic IOLs, in comparison to PMMA and silicone IOLs. Cells grown on acrylic lenses formed a confluent epithelial monolayer. Migration of lens epithelial cells under the acrylic lens was substantially blocked in an in vitro assay. In contrast, cells grown on PMMA and silicone lenses displayed a spindle-shaped, myofibroblast-like morphology, increased apoptosis, reduced adhesion, and enhanced production of EMT proteins such as fibronectin and type I collagen. The migration of lens epithelial cells under PMMA and silicone IOLs was substantial in the in vitro assay. Conclusion This report demonstrates that hydrophobic acrylic lenses are more capsular biocompatible than PMMA and silicone lenses. The in vitro assays are reliable measurements for evaluating the responses of human lens epithelial cells to different IOL materials, and could advance our understanding of the preferential capsular opacification conferred by different IOL materials.