THE NOVEL USE OF HIGH-FLOW POLYIMIDE CANNULAS TO IMPROVE SILICONE OIL INJECTABILITY IN VITREORETINAL SURGERY.

PURPOSE: The injection of high-viscosity silicone oil lengthens injection time. New polyimide cannulas offer a greater inner diameter than conventional metal cannulas at the same gauge. We compared the injection time for polyimide and metal cannulas at 23 G for a variety of silicone oils including a 12,500-mPas prototype oil. METHODS: In this laboratory study, injection time was measured three times per cannula and per oil. Warming the oil before injection to up to 42°C was also evaluated. Finally, the feasibility of polyimide cannulas was tested in vitrectomized porcine eyes. RESULTS: The 23-G polyimide cannula mostly decreased injection times. The time to inject 5 mL of Siluron Xtra and Siluron 5000 decreased by 6:02 (76.9%) minutes (483 vs. 121 seconds) and 12:01 (74.7%) minutes (973 vs. 252 seconds), respectively. Although the 23-G metal cannula failed to inject 12,500 mPas oil, 5 mL was injected in 10:21 minutes using the polyimide cannula. Prewarming Siluron 5000 to 42°C lowered the injection time by 9.0% and by 12.1% when using the metal or polyimide cannula, respectively. CONCLUSION: Polyimide cannulas allow a clinically relevant decrease in injection time. They may not only shorten surgery time but could also ease the use of next-generation ultra-high-viscosity silicone oils. Prewarming silicone oil leads to decreased injection times.

In-vitro glistening formation in six different foldable hydrophobic intraocular lenses.

BACKGROUND: Glistenings describe small, refractile microvacuoles that may arise within the intraocular lens (IOL) material and reduce the patients' quality of vision. Lenses composed of hydrophobic acrylic material are particularly affected by glistening formation. In this study, we compared the tendency of glistening formation in six different types of hydrophobic acrylic intraocular lenses (IOLs). METHODS: We used a well-established accelerated laboratory method to develop glistenings in the following IOLs: Vivinex XY1 (Hoya), AcrySof SN60WF (Alcon), Tecnis ZCB00 (AMO), Avansee PN6A (Kowa), Aktis SP NS-60YG (Nidek), and CT Lucia 601P (Zeiss). IOLs were first immersed in saline at 45 °C for 24 h and then at 37 °C for 2.5 h in a water bath. Microvacuole (MV) density and size (Miyata grading) were documented and calculated using an image analysis program. RESULTS: The mean glistening density [MV/mm2] and mean Miyata grading (in brackets) were: Vivinex: 11.6 ± 5.7 (0), SN60WF: 264.4 ± 110.3 (2.6), Tecnis: 6.0 ± 2.8 (0), Avansee: 2.2 ± 0.7 (0), Aktis: 851.4 ± 59.4 (3+) and CT Lucia: 71.0 ± 71.6 (1). CONCLUSIONS: While all tested IOLs showed glistenings with the accelerated laboratory method, the Aktis and SN60WF showed the highest microvacuole density, followed by the CT Lucia. In comparison, the Vivinex, Tecnis, and Avansee IOLs showed far fewer number of glistenings.

Comparative analysis of in vitro accelerated glistening formation in foldable hydrophobic intraocular lenses.

PURPOSE: To analyse and compare the propensity to form glistenings in 4 different types of hydrophobic acrylic intraocular lenses (IOLs): Alcon AcrySof ® MA60AC, HOYA iSert® PC-60AD, Bausch&Lomb enVista, and Kowa Avansee™ PU6A. METHODS: We used an accelerated laboratory method to create glistenings. IOLs were first immersed in saline at 45 °C for 24 h and then at 37 °C for 2.5 h. Microvacuole (MV) density and size were documented and calculated using an image analysis program. RESULTS: Median density of glistenings [MV/mm2] for Alcon AcrySof ® MA60AC was 623 (range 507-804), for HOYA iSert® PC-60AD 1358 (range 684-2699), for Bausch&Lomb enVista 2 (range 1-2), and for Kowa Avansee™ PU6A 1 (range 1-4). The prevailing MV size was: 0-5 µm for Hoya IOLs, 5-10 µm for Alcon IOLs, 20-50 µm for Bausch&Lomb IOLs, and 5-50 µm for Kowa IOLs. CONCLUSIONS: Glistenings could be induced in all studied IOLs using the accelerated laboratory method. The Alcon AcrySof ® MA60AC and HOYA iSert® PC-60AD IOLs showed MV of high density, while the glistenings in the Hoya IOLs were smaller in size compared to the Alcon IOLs. The MV density was minimal in the Bausch&Lomb enVista and Kowa Avansee™ PU6A IOLs. The propensity of the Alcon AcrySof ® MA60AC IOLs to form glistenings in vitro correlated with the findings of clinical results that are already published.

Glistening formation in a new hydrophobic acrylic intraocular lens.

BACKGROUND: The formation of fluid-filled microvacuoles, termed glistenings, is a common complication of intraocular lenses (IOLs) made from hydrophobic acrylate. Using our well-established in-vitro laboratory method, we evaluated a new IOL material's resistance to glistening formation. METHODS: An in-vitro stress test for glistening induction was performed on 20 samples of hydrophobic acrylic IOLs: ten of the new Eyecryl ASHFY600 (Biotech Vision Care, Ahmedabad, India) compared with ten samples of AcrySof IQ SN60WF (Alcon, Fort Worth, USA). The number of microvacuoles per square millimetre (MV/mm2) was evaluated in five sections of each IOL. The results for each model were compared and rated on a modified Miyata Scale for grading glistening severity. RESULTS: In all cases, glistening number was higher in the central section of the IOL optic than in the periphery. Mean number of MV/mm2 was highest in the central part of the AcrySof IQ SN60WF, with 41.84 (±27.67) MVs/mm2. The lowest number of glistenings was found in the five sections of the Eyecryl ASHFY600 with 0.52 (±0.24) MVs/mm2. Mean value of the Eyecryl ASHFY600 IOL, using the Miyata Scale, was Zero. CONCLUSION: In this in-vitro laboratory study, the new hydrophobic acrylic IOL showed a high resistance to microvacuole formation. Results from this in-vitro study suggest that glistening numbers will be low in clinical use in the Eyecryl ASHFY600.

In vitro comparative optical bench analysis of a spherical and aspheric optic design of the same IOL model.

BACKGROUND: To analyse objective optical properties of the spherical and aspheric design of the same intraocular lens (IOL) model using optical bench analysis. METHODS: This study entailed a comparative analysis of 10 spherical C-flex 570 C and 10 aspheric C-flex 970 C IOLs (Rayner Intraocular Lenses Ltd., Hove, UK) of 26 diopters [D] using an optical bench (OptiSpheric, Trioptics, Germany). In all lenses, we evaluated the modulation transfer function (MTF) at 50 lp/mm and 100 lp/mm and the Strehl Ratio using a 3-mm (photopic) and 4.5-mm (mesopic) aperture. RESULTS: At 50 lp/mm, the MTF values were 0.713/0.805 (C-flex 570 C/C-flex 970 C) for a 3-mm aperture and 0.294/0.591 for a 4.5-mm aperture. At 100 lp/mm, the MTF values were 0.524/0.634 for a 3-mm aperture and 0.198/0.344 for a 4.5-mm aperture. The Strehl Ratio was 0.806/0.925 and 0.237/0.479 for a 3-mm and 4.5-mm aperture respectively. A Mann-Whitney U test revealed all intergroup differences to be statistically significant (p < 0.01). CONCLUSION: The aspheric IOL design achieved higher MTF values than the spherical design of the same IOL for both apertures. Moreover, the differences between the two designs of the IOL were more prominent for larger apertures. This suggests that the evaluated IOL provides enhanced optical quality to patients with larger pupils or working under mesopic conditions.

In-vitro assessment of a novel intraocular lens made of crosslinked polyisobutylene.

PURPOSE: To describe and analyse the particularities of the material and the optical quality of the first intraocular lens (IOL) (Eyedeal® lens) made of crosslinked polyisobutylene (xPIB). METHODS: We assessed the material quality using an accelerated ageing process (to provoke glistenings) and compared values with a control, AcrySof® lens. Using the sessile drop method, the contact angle of the new IOL was measured. Images of the lens surface were recorded by scanning electron microscopy (SEM). Optical quality was assessed by measuring the labeled power and modulation transfer function (MTF) using standard metrology equipment (OptiSpheric IOL PRO2). RESULTS: The Eyedeal® lens had an average glistening density result of 7.46 ± 3.78 MV/mm2 compared to the control AcrySof® whose glistenings number was 142.42 ± 72.47 MV/mm2. The contact angle was 97.2° whereas the angle of AcrySof material is between 73.3 ± 2.4° and 84.4 ± 0.1°. Using SEM, Eyedeal® lenses were examined and all appeared to be comparable to modern IOLs made of acrylic materials. The power and MTF values were normal and conformed to ISO standards. CONCLUSIONS: In the laboratory, the new Eyedeal® lens showed equivalence to current hydrophobic- or hydrophilic-acrylic lens models. It showed superiority in its glistening density result compared to the control lens.

Implantation of three-piece silicone toric additive IOLs in challenging clinical cases with high astigmatism.

PURPOSE: To analyze the refractive outcomes and safety of three-piece silicone toric sulcus-fixated add-on intraocular lenses (IOLs) (HumanOptics/Dr.Schmidt Intraocularlinsen, Erlangen, Germany) in complex clinical cases with high astigmatism such as in cases with previous penetrating keratoplasty. METHODS: Interventional case series of 21 eyes of 20 patients enrolled at two German centers. Functional results including power vector analysis, accuracy of IOL power calculation, rotational stability, and postoperative complications were evaluated from 2 months to 6 years postoperatively. RESULTS: The preoperative subjective cylinder exceeded or was equal to -6.00 diopters (D) in 81% of eyes (range: -2.00 to -17.00 D). The median follow-up period was 7.6 months (range: 57 days to 6 years). The efficacy analysis focused on the 2 to 6 months follow-up visit. Postoperatively, there was a median reduction of astigmatism by 70.59% (subjective cylinder range: 0.00 to -5.00 D), improvement of uncorrected distance visual acuity, and unchanged median corrected distance visual acuity. The attempted spherical equivalent was achieved within ± 0.50 D in 45% and within ± 1.00 D in 65% of cases. Five eyes received secondary surgical alignment of axis. Other complications related to the surgical procedure were mainly transient shortly after implantation, such as intraocular pressure elevation (2 of 21 eyes) or corneal edema (2 of 21 eyes). Persisting changes were seen only in rare cases and included pigment dispersion (1 of 21 eyes) or corneal edema requiring a second keratoplasty within 9 months after surgery (2 of 21 eyes). CONCLUSIONS: Toric add-on IOLs may be useful in reducing high astigmatism and anisometropia and increasing spectacle independence even in complex clinical conditions with high refractive errors.

Physicochemical Properties of Explanted Silicone Oil After Use as an Intraocular Tamponade.

PURPOSE: We studied the effects of exposure to biological media within the eye, such as contamination with lipophilic and amphiphilic substances, on the physicochemical parameters of silicone oil used as an intraocular tamponade. METHODS: We removed silicone oil with visible emulsification from 15 patients and measured each sample for shear viscosity and surface tension. We induced in vitro emulsification with balanced salt solution. Using the zeta-potential, we evaluated the emulsion droplet's electrochemical stability. We repeated all experiments in a control group of unused oil. Electrochemical stability and viscosity were additionally measured in oils with high-molecular-weight components. RESULTS: We recovered silicone oils implanted between 30 and 506 days (mean, 196 days). Viscosity did not differ between explanted and control groups. Surface tension and zeta potential remained unchanged (P = 0.61 and P = 0.84, respectively). All oils showed a significant correlation of viscosity with temperature (P < 0.01 for all). Oils with added high-molecular-weight components showed a lower emulsion stability. CONCLUSIONS: Prolonged contact to hydrophilic biological media does not alter high-viscosity silicone oil's physicochemical parameters. During typical durations of intraocular use, lipophilic and amphiphilic molecules had no deleterious effect. The addition of high-molecular-weight components might decrease the silicone oil's electrochemical emulsion stability, possibly easing the confluence of emulsion droplets. TRANSLATIONAL RELEVANCE: Although the physicochemical parameters of silicone oils are not altered after clinically relevant durations within the eye, emulsion stability significantly differs between oil types.

Retropupillary fixation of iris-claw intraocular lens versus transscleral suturing fixation for aphakic eyes without capsular support.

PURPOSE: Retropupillary fixation of an iris-claw intraocular lens (IOL) (Verisyse, Abbott Medical Optics) was performed for aphakic eyes without sufficient capsular support, and safety and recovery of the procedure were compared with transscleral suturing fixation. METHODS: This interventional case series comprised 11 eyes of 10 aphakic patients without capsular support undergoing retropupillary fixation of the Verisyse, and 21 eyes of 20 patients undergoing transscleral suturing fixation of foldable acrylic IOLs (15 eyes of 14 patients, SuperFlex620H [Rayner Intraocular Lenses Ltd]) and polymethylmethacrylate IOLs (6 eyes of 6 patients, CP60NS [CORNEAL Laboratoire]). Surgical time was measured. Corrected distance visual acuity (CDVA) and intraocular pressure (IOP) were examined preoperatively and 1 day, 1 and 2 weeks, and 1 and 6 months postoperatively. RESULTS: No complications occurred in the Verisyse group, whereas complications were reported in seven eyes in the transscleral suturing fixation group throughout follow-up. Mean CDVA (logMAR) in the transscleral suturing group 1 day after surgery was significantly worse than preoperative CDVA (P<.05). In the Verisyse group, no significant changes in CDVA were noted at any time point. Mean IOP at postoperative day 1 in the transscleral suturing fixation group was significantly higher than that in the Verisyse group (P=.0126). Mean surgical time of Verisyse implantation (20.0 ± 8.9 min) was significantly shorter than transscleral suturing fixation (49.7 ± 18.9 min) (P<.0001). CONCLUSIONS: Retropupillary fixation of an iris-claw IOL provides early visual recovery, has a low risk of postoperative increase in IOP, and is a time-saving method compared with transscleral suturing fixation for aphakic eyes without sufficient capsular support.

Quantitative evaluation of microvacuole formation in five intraocular lens models made of different hydrophobic materials.

In this laboratory study, we assessed the resistance to microvacuole (glistening) formation in hydrophobic intraocular lenses (IOLs). Glistenings were induced in five lenses each of five different hydrophobic acrylic IOL models, using an established in vitro laboratory model: 800C (Rayner, Worthing, UK), AcrySof SN60WF (Alcon, Fort Worth, USA), Tecnis ZCB00 (Johnson & Johnson Vision, Santa Ana, USA), Vivinex XY1 (Hoya, Tokyo, Japan) and CT Lucia 611P (Zeiss, Oberkochen, Germany). We evaluated the number of microvacuoles per square millimeter (MV/mm2) in the central part of each IOL. Results were analyzed statistically, and mean glistening numbers were ranked, with the highest in the SN60WF which had 66.0 (±45.5) MVs/mm, followed by the 611P with 30.7 (±8.4) MVs/mm2. The 800C and XY1 showed comparable values of 2.0 (±3.6) and 2.7 (±2.4) MVs/mm2, respectively. ZCB00 had the lowest number with 0.9 (±0.6) MVs/mm2. This study shows that the resistance to glistening formation differs depending on the hydrophobic acrylic copolymer composition of the IOL material. Some IOLs from current clinical use are still prone to develop glistenings whereas others, including the ZCB00, 800C and XY1 show high resistance to microvacuole formation.

The impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens.

PURPOSE: To study the effect of glistenings on the optical quality of a hydrophobic acrylic intraocular lens (IOL). SETTING: David J. Apple Laboratory, Heidelberg, Germany. DESIGN: An in vitro laboratory study. METHODS: An accelerated aging protocol was used to induce glistenings (microvacuoles) in 38 hydrophobic acrylic IOLs. The IOLs were warmed to 45°C and then cooled to 37°C. Image analysis of light-microcopy photographs determined the number and size of microvacuoles (MV). A classification was applied based on the glistening number per mm2: grade 0 (none), grade 1 (1-100), grade 2 (101-200), grade 3 (201-500) and grade 4 (more than 500). An optical bench was used to measure each IOL's modulation transfer function (MTF) and Strehl ratio to evaluate the impact of glistenings on image quality. RESULTS: Glistenings were observed in all IOLs. The mean glistening numbers ± SD (MV/mm2) in grades 1 through 4 were 74 ± 12.7, 142 ± 22.2, 297 ± 76.2, and 1509 ± 311.9, respectively. The mean glistening sizes in grades 1 through 4 were 13.28 ± 3.85 µm, 15.88 ± 2.08 µm, 16.85 ± 3.23 µm, and 15.27 ± 2.25 µm, respectively. Statistical analysis showed that grades 1 through 3 did not change the optical quality; however, in grade 4, the MTF and the Strehl ratio were significantly affected. CONCLUSION: A limited number of glistenings (<500 MV/mm2) had no effect on the image quality. Although statistically significant deteriorations in the MTF and the Strehl ratio were observed in grade 4, the effects found were small and are unlikely to affect the visual quality.

Material Analysis and Optical Quality Assessment of Opacified Hydrophilic Acrylic Intraocular Lenses After Pars Plana Vitrectomy.

PURPOSE: Explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after pars plana vitrectomy (PPV) were assessed for material change and optical quality, in an in vitro laboratory study. DESIGN: Retrospective observational case series. METHODS: Ten opacified IOLs after PPV with intraocular gas injection were analyzed in a laboratory setting. Analyses included evaluation of patients' medical history, optical quality assessment, light microscopy, histologic staining, scanning electron microscopy, and energy dispersive x-ray spectroscopy. RESULTS: In all 10 IOLs a thin layer of calcium phosphate that had accumulated underneath either the anterior or posterior optical surface in a central circular area of the IOL optic caused the opacification. The calcifications lead to deterioration of the modulation transfer function (MTF) across all spatial frequencies. CONCLUSION: PPV with instillation of gas into a pseudophakic eye with an acrylic hydrophilic lens seems to increase the risk for secondary calcification irrespective of the manufacturer. In these cases, IOL exchange is the only treatment option available. Since IOL exchange is associated with a high intraoperative complication rate, our results suggest to consider the risk of IOL calcification when implanting hydrophilic acrylic IOLs.

Glistening Formation and Light Scattering in Six Hydrophobic-Acrylic Intraocular Lenses.

PURPOSE: To study the glistening formation in various hydrophobic-acrylic intraocular lens (IOL) models, and to evaluate the effect of glistenings on light scattering in these IOLs. DESIGN: Laboratory investigation. METHODS: The susceptibility of the hydrophobic-acrylic material to develop glistenings was evaluated in 6 IOL models. Accelerated lens aging was induced by immersing the IOLs in a solution at 45 C for 24 hours and cooled to 37 C for 2.5 hours. Light microscopy and image acquisition were performed. Glistening statistics-that is, microvacuoles' (MV) number and size-were derived from image analysis. Light scattering was measured using a clinical device featuring an adaptation for in vitro IOL assessment. RESULTS: The number of glistenings differed among the studied IOLs and ranged from 0 to 3532 MV/mm2. In 1 model, glistenings were found only at the periphery, with diffuse light scattering observed centrally despite the absence of microvacuoles. The mean size of glistenings ranged from 5.2 to 10.2 µm. The mean straylight parameter of the IOLs increased from 0.6 to 5.0 deg2/sr after accelerated aging. Straylight elevation demonstrated a proportional relationship with the glistening number. CONCLUSIONS: We showed that hydrophobic-acrylic lenses differ in their resistance to glistenings, as one group proved to be glistening-free, but the other models revealed varying grades of glistenings. Moreover, we demonstrated that the presence of glistenings results in increased straylight, and that straylight proportionally depends on the glistenings number irrespective of the IOL model. However, more research is needed to confirm that the relationship we found holds for all hydrophobic-acrylic IOLs.

Influence of 360-degree enhanced optic edge design of a hydrophilic acrylic intraocular lens on posterior capsule opacification.

PURPOSE: To compare the rate of posterior capsule opacification (PCO) with the single-piece hydrophilic acrylic foldable Rayner Centerflex 570H intraocular lens (IOL), which has a sharp optic edge design excluding the optic-haptic junction, and the Rayner C-flex 570C IOL, which has an improved 360-degree sharp edge. SETTING: Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. METHODS: As part of a multicenter U.S. Food and Drug Administration (FDA) study, 42 patients who had implantation of a C-flex IOL in 1 eye after uneventful phacoemulsification were enrolled. Six and 12 months postoperatively, PCO was evaluated by retroillumination photographs using Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software. The data were then compared with those in a matched group of patients with a Centerflex IOL who participated in a previous FDA study. RESULTS: The mean age of the patients with the C-flex IOL was 71.5 years +/- 8.2 (SD) There was a statistically significant difference in EPCO scores between the C-flex group and Centerflex group. Six months after surgery, the mean EPCO value (total IOL optic) was 0.07 +/- 0.17 in the C-flex group (n = 37) and 0.20 +/- 0.20 in the Centerflex group (n = 36) (P<.01, Wilcoxon test). By 12 months, the mean had increased to 0.16 +/- 0.20 in the C-flex group (n = 37) and 0.35 +/- 0.22 in the Centerflex group (n = 31) (P<.01, Wilcoxon test). CONCLUSIONS: The C-flex IOLs showed good functional results and significantly lower PCO formation than the earlier model Centerflex IOL. The enhanced edge of the C-flex IOL seemed to improve PCO prevention clinically.

Material Analysis of Spontaneously Subluxated Iris-Fixated Phakic Intraocular Lenses.

PURPOSE: To conduct a material analysis of spontaneously subluxated iris-fixated phakic intraocular lenses (IOLs) using light and scanning electron microscopy. METHODS: Six explanted Artisan/Verisyse and Artiflex/Veriflex IOLs (Ophtec, Groningen, Netherlands/AMO, Santa Ana, CA) were analyzed in a laboratory using light and scanning electron microscopy. Four of the IOLs had been explanted after spontaneous subluxation leading to a decrease in visual acuity, whereas the remaining two IOLs did not demonstrate signs of disenclavation but had been explanted in the course of planned cataract surgery and thus served as the control in this study. RESULTS: Light microscopy enabled the detection of clear deformations of the fixation arms on one or both haptics of the lens that had subluxated, and scanning electron microscopy revealed micro-cracks in the material. The deformations, which appeared to have been caused by some form of manipulation of the fixation arms, meant that adequate closure of the fixation arms was no longer possible and a reliable fixation in the iris stroma was unattainable. At least three of the lenses had been implanted with the use of an IOL haptic expander for enclavation, which may have contributed to the malformation of the haptics. The two control lenses exhibited no signs of material deformation or subsequent disenclavation. CONCLUSIONS: Deformations of the haptics of iris-fixated phakic IOLs can cause irreversible damage leading to disenclavation and inadequate re-enclavation. In such cases, explantation appears to be the only therapeutic option. It is important to adhere to an appropriate implantation technique to reduce the risk of spontaneous subluxation. [J Refract Surg. 2016;32(9):618-624.].

Removal times for a dispersive and a cohesive ophthalmic viscosurgical device correlated with intraocular lens material.

PURPOSE: To investigate the removal times of ophthalmic viscosurgical devices (OVDs) with different intraocular lens (IOL) designs and materials. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA, and Heidelberg IOL & Refractive Surgery Research Group, Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: In a standardized laboratory setup, the Miyake-Apple posterior view video technique was used to evaluate OVD removal from capsular bags in human autopsy eyes implanted with poly(methyl methacrylate) (PMMA), silicone, and acrylic IOLs. The cohesive OVD ProVisc (sodium hyaluronate 1.0%) and the dispersive OVD Viscoat (sodium hyaluronate 3.0% and chondroitin sulfate 4.0%) were stained with fluorescein for better visualization. The open-sky preparation and an Alcon Series 20000 Legacy phaco machine with a flow rate of 25 mL/min and a vacuum setting of +500 mm Hg (maximum irrigation/aspiration) were used. The time needed for complete removal of the cohesive and dispersive OVDs with each IOL type was measured and analyzed statistically. RESULTS: The mean removal times for both OVDs were as follows: Alcon MZ60BD PMMA IOL-25.0 seconds +/- 3.7 (SD) (Viscoat), 15.9 +/- 6.9 seconds (ProVisc); Alcon AcrySof MA60BM IOL-35.5 +/- 10.0 seconds (Viscoat), 25.6 +/- 4.7 seconds (ProVisc); Chiron/Bausch & Lomb C1043 silicone IOL-46.5 +/- 10.5 seconds (Viscoat), 17.3 +/- 2.1 seconds (ProVisc); AMO SI-30 silicone IOL-33.5 +/- 3.1 seconds (Viscoat), 15.3 +/- 6.3 seconds (ProVisc); and Pharmacia 912 silicone IOL-18.3 +/- 5.8 seconds (Viscoat), 19.8 +/- 4.3 seconds (ProVisc). CONCLUSIONS: Differences in OVD removal times were detected. The removal time for the cohesive OVD correlated with the IOL material. Overall, the time needed for complete removal was significantly longer for the dispersive OVD than for the cohesive OVD.

Removal times and techniques of a viscoadaptive ophthalmic viscosurgical device.

PURPOSE: To analyze removal techniques for Healon5 (sodium hyaluronate 2.3%). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Charleston, South Carolina, USA, and Department of Ophthalmology, Ruprecht-Karls-University, Heidelberg, Germany. METHODS: In a standardized laboratory setup, the Miyake-Apple posterior view video technique in human autopsy eyes was used to evaluate removal of an ophthalmic viscosurgical device (OVD) from capsular bags implanted with poly(methyl methacrylate), silicone, and acrylic intraocular lenses (IOLs). Healon5 was stained with fluorescein for better visualization. Open-sky preparation and an Alcon Legacy Series 20000 phaco machine with a flow rate of 25 mL/minute and a vacuum setting of +500 mm Hg (maximum irrigation/aspiration [I/A]) were used. With Technique 1, the I/A tip was placed on the center of the IOL and maximum aspiration was applied. With Technique 2 (modified rock 'n roll technique), the I/A tip was moved in quick circular movements on top of the IOL to break the OVD chains and facilitate aspiration. RESULTS: With Technique 1, the mean removal time was 59.0 seconds +/- 23.1 (SD) and with Technique 2, 23.6 +/- 10.3 seconds (P =.004). The removal time of Healon5 correlated with the IOL material. With Technique 2, removal was fastest with silicone IOLs (13.5 +/- 2.1 seconds) followed by PMMA IOLs (17.5 +/- 2.1 seconds). With acrylic IOLs, remnants of the OVD trapped behind the IOL optic resulted in a longer removal time of 34.1 +/- 1.2 seconds. CONCLUSIONS: Healon5 was completely removed from the capsular bag with the modified rock 'n roll technique. With acrylic IOLs, remnants can be trapped behind the optic and may be overlooked with an unstained OVD. Aspiration behind the optic is recommended with this IOL type.

Rates and causes of intraoperative removal of foldable and rigid intraocular lenses: clinicopathological analysis of 100 cases.

PURPOSE: To analyze the rates of and reasons for intraoperative explantation of foldable and rigid intraocular lenses (IOLs) to determine the complication profile of each IOL design. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: The study comprised data analysis of foldable (n = 85) and rigid (n = 15) IOL specimens that were explanted immediately after primary implantation. RESULTS: Eighty-five foldable intraoperative explants were accessioned. These comprised 14.5% of the 586 foldable IOL explants received between January 1988 and September 2000. There were 15 rigid poly(methyl methacrylate) (PMMA) intraoperative explants out of 2077 rigid explant specimens (0.7%). Fifty-one (60%) of the foldable IOLs requiring intraoperative explantation were the 1-piece silicone plate-haptic large-hole design, and 29 (34.1%) were the 3-piece silicone polyimide-haptic design. The most frequent reason for explantation of both designs was optic damage, 37.3% in the large-hole design and 55.2% in the polyimide design. Optic damage did not occur in rigid PMMA IOLs. CONCLUSION: Some foldable IOL designs have a higher risk of damage during surgical insertion than rigid designs. Two modern foldable IOLs, the silicone plate-haptic large-hole and the silicone polyimide-haptic, appear to be more prone to damage during folding, loading, and implantation than other IOLs.

Comparison of Nd : YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, or acrylic intra-ocular lenses in four European countries.

PURPOSE: The aim of this study was to compare the incidence of Nd : YAG laser capsulotomy after cataract surgery according to the type of intra-ocular lens material (PMMA, silicone, hydrophilic acrylic, hydrophobic acrylic) implanted in four European countries (France, Italy, Germany, Spain). DESIGN: A retrospective record review. PARTICIPANTS: A review of 1525 patients (first operated eye), aged 50 to 80 years, operated on for cataract in 1996 or 1997 in 16 surgical centers (4 per country). METHODS: The study employed a retrospective cohort design. Charts were reviewed to collect information during at least a three-year period following cataract surgery to identify patients who underwent Nd : YAG laser capsulotomy postoperatively. MAIN OUTCOME MEASURES: Data on the type of intra-ocular lens implanted was extracted from the patient notes, as was the date and outcome of the Nd : YAG laser intervention. Kaplan-Meier survival curve analysis with the time to Nd : YAG laser was performed on the data. RESULTS A total of 1525 patients (first operated eye) were available for the study (n = 294 for hydrophilic acrylic, n = 384 for PMMA, n = 421 for hydrophobic acrylic, n = 426 for silicone). There was a highly statistically significant difference between the IOL groups for the incidence of posterior capsule opacification (p < 0.001) and for Nd : YAG laser treatment (p < 0.001). The mean delay of Nd : YAG laser treatment from the date of cataract operation was 2.48 years (+/-1.70, ranging from 0 to 5.88 years). The rate of Nd : YAG laser capsulotomy over the follow-up period was lowest in the hydrophobic acrylic group (7.1%), followed by silicone (16.2%), PMMA (19.3%) and hydrophilic acrylic (31.1%), respectively. CONCLUSIONS: A low incidence of posterior capsular opacification (PCO) and Nd : YAG laser treatment was detected in hydrophobic acrylic IOLs in comparison to three other types of IOLs implanted in a large cohort of persons with age-related cataract. Choice of IOL type may reduce the need for Nd : YAG laser treatment, although further research on the reasons for this is needed.

Prevention of posterior capsule opacification using different intraocular lenses (results of one-year clinical study).

AIM: To evaluate and to compare the preventive effect of different intraocular lenses from different material with a round or sharp optic edge design on posterior capsule opacification. METHODS: Our clinical study included 165 patients. Mean follow-up was 12.4+/-0.9 months, mean patient age was 67.5+/-7.8 years. Patients in the group 1 (n=46) were implanted acrylic three-piece hydrophobic intraocular lenses, sharp optic edge (AcrySof, MA3OBA, Alcon), in the group 2 (n=38)--acrylic hydrophobic single piece intraocular lenses, sharp optic edge (AcrySof, SA3OAL, Alcon), in the group 3 (n=39)--silicone three-piece intraocular lenses, sharp optic edge (CeeOn 911A, Pharmacia), and in the group 4 (n=42)--polymethyl methacrylate single piece intraocular lenses, round optic edge (Crystal, 5T, Alcon). The posterior capsule opacification was evaluated for the entire optic and in the central 3-mm zone using EPCO 2000 Software. RESULTS: Posterior capsule opacification values of the entire optic were 0.002+/-0.001 in the AcrySof MA3OBA group, 0.007+/-0.002 in the AcrySof SA3OAL group, 0.002+/-0.001 in the CeeOn 911A group, 0.029+/-0.008 in the polymethyl methacrylate intraocular lens group 6 months after surgery. The values were 0.011+/-0.005, 0.025+/-0.006, 0.014+/-0.005 and 0.122+/-0.021, respectively, one year after surgery. The intraocular lenses types with sharp-edge design (acrylic and silicone) showed significantly lower posterior capsule opacification values than round-edge optic design polymethyl methacrylate lenses (p<0.05). Posterior capsule opacification values of the central 3-mm zone were 0.000+/-0.000 in the AcrySof MA3OBA group, 0.001+/-0.001 in the AcrySof SA3OAL group, 0.000+/-0.000 in the CeeOn 911A group, 0.002+/-0.001 in the polymethyl methacrylate intraocular lens group 6 months after surgery. The values were 0.0001+/-0.0001, 0.018+/-0.007, 0.004+/-0.002 and 0.028+/-0.009, respectively, one year after surgery. Posterior capsule opacification values differences between AcrySof MA3OBA and polymethyl methacrylate intraocular lenses' groups and between CeeOn 911A and polymethyl methacrylate intraocular lenses' groups one year after cataract surgery were established (p<0.05). CONCLUSIONS: The sharp-edge foldable intraocular lenses types (AcrySof MA3OBA, AcrySof SA3OAL, CeeOn 911A) showed statistically significant difference in posterior capsule opacification values in one-year follow-up time. The effect of these foldable lenses for prevention of posterior capsule opacification is mainly a result of rectangular, sharp-edged optic design, which creates a sharp capsular bend. A role of material of intraocular lenses (hydrophobic acrylate and silicone) in prevention of posterior capsule opacification during one-year follow-up was not established.