Foldable Silicone Intraocular Lens Research Articles

Viscoanaesthesia in cataract surgery: a prospective, randomized clinical trial

We aimed to compare viscoanaesthesia (VisThesia) with intracameral lidocaine in cataract surgery carried out under topical anaesthesia. In this prospective study 98 patients were randomly assigned to receive VisThesia (group 1, n = 49) or 0.5 cc of 1% unpreserved lidocaine (group 2, n = 49). All surgery was carried out by one surgeon using clear corneal technique. Pachymetry, the status of the cornea and anterior chamber, and intraocular pressure (IOP) were checked pre- and postoperatively. Mean pain scores were 0.12 (maximum: 3) in group 1 and 0.37 in group 2; the difference between the groups was not statistically significant (95% confidence interval [CI] 0.003-0.487; p = 0.05). A total of 48 patients in group 1 (98%) and 49 in group 2 (100%) reported no discomfort or only mild discomfort. No significant differences in flare and cells in the anterior chamber or IOP were found between the two study groups. There was a significantly greater frequency of corneal oedema in group 1 (p = 0.001). Postoperative central corneal thickness values were also significantly higher in group 1 (95% CI 11.64-57.24; p = 0.003). Results suggest that viscoanaesthesia provides a level of comfort during cataract surgery under topical anaesthesia similar to that facilitated by intracameral lidocaine. However, patients who are given viscoanaesthesia may have increased risk for postoperative corneal oedema.

Comparison of PMMA, silicone and acrylic intraocular lenses in combined phacoemulsification and trabeculectomy

目的 比较青光眼白内障联合术中植入不同材料人工晶状体(IOL)的临床效果.方法 回顾性分析行青光眼白内障联合术70例(76眼),其中植入PMMA IOL 30例(36眼),硅胶IOL 23例(23眼),丙烯酸酯折叠IOL 17例(17眼).对治疗效果进行评价,平均随访期限为10.5月.结果 3组间术后眼压和最佳矫正视力差异无统计学意义.前房纤维素样渗出物和IOL表面沉积物发生率,硅胶组高于PMMA组和丙烯酸酯组,但差异无统计学意义.后发障发生率,丙烯酸酯组和硅胶组显著低于PMMA组,差异有统计学意义.结论 行青光眼白内障联合术植入PMMA,硅胶与丙烯酸酯IOL在降眼压和提高视力方面具有相似的效果.但硅胶IOL的前房纤维素样渗出物及IOL表面沉积物发生率高于PMMA和丙烯酸酯IOL.丙烯酸酯和硅胶IOL的后发障发生率低于PMMA IOL。

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

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. Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey. 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. 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. Heavy silicone oil acted the same as silicone oil and covered the entire surface of silicone IOLs.

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.

Intraocular pressure rise after small incision cataract surgery: a randomised intraindividual comparison of two dispersive viscoelastic agents

AIMTo evaluate the effects of the dispersive viscoelastic agents Ocucoat (hydroxypropyl methylcellulose 2%) and Viscoat (sodium chondroitin sulphate 4%–sodium hyaluronate 3%) on postoperative intraocular pressure (IOP) after bilateral small incision...

Foldable silicone versus poly(methyl methacrylate) intraocular lenses in combined phacoemulsification and trabeculectomy

Purpose To compare the outcome of phacotrabeculectomy with implantation of poly(methyl methacrylate) (PMMA) or foldable silicone intraocular lenses (IOLs). Methods Thirty patients were randomized to receive a 5.5 mm PMMA IOL through a 5.0 mm incision or a foldable silicone IOL (Allergan SI-30) through a 3.2 mm incision. Visual acuity, intraocular pressure (IOP), bleb survival, inflammation, endothelial cell changes, and complications were examined at intervals up to 6 months. Results There was no difference between the 2 groups in final visual outcome, final IOP control, bleb survival, and endothelial cell changes. Two months after surgery, there was significantly more inflammation in the silicone IOL group than in the PMMA group ( P < .05). The silicone group had a significantly higher combined complication rate including iris capture, choroidal effusion, and epiretinal membrane formation ( P < .05). Conclusions Foldable silicone IOLs were comparable to conventional PMMA lenses in visual outcome, IOP control, bleb formation, and endothelial changes. However, some silicone lenses are associated with an increased risk of recurrence of inflammation and a higher final complication rate in combined cataract and filtration surgery.

Intraocular pressure after small incision cataract surgery with Healon5 and Viscoat

PurposeTo evaluate the effect of Healon®5 (sodium hyaluronate) and Viscoat® (sodium chondroitin sulfate–sodium hyaluronate) on intraocular pressure (IOP) after bilateral small incision cataract surgery. SettingDepartment of Ophthalmology, University of Vienna, Vienna, Austria. MethodsThis prospective randomized study comprised 70 eyes of 35 consecutive patients with age-related cataract in both eyes scheduled for bilateral small incision cataract surgery. The patients were randomly assigned to receive Healon5 or Viscoat during cataract surgery in the first eye. The second eye received the other viscoelastic substance. Cataract surgery was performed in an identical fashion in both eyes, with a temporal 3.5 mm sutureless posterior limbal incision, phacoemulsification, and implantation of a foldable silicone intraocular lens. The IOP was measured preoperatively and 6 hours, 20 to 24 hours, and 1 week postoperatively. ResultsAt 6 hours after surgery, the mean IOP increased by 5.2 mm Hg ± 5.3 (SD) in the Healon5 group (P < .0001) and by 10.1 ± 8.7 mm Hg in the Viscoat group (P < .0001). The increase was significantly higher in the Viscoat group than in the Healon5 group (P = .0016). Intraocular pressure spikes of 30 mm Hg or more occurred in 2 eyes in the Healon5 group and in 10 eyes in the Viscoat group (P = .0112). Twenty to 24 hours and 1 week postoperatively, the mean IOP in the 2 groups was not statistically different. ConclusionsViscoat caused a significantly higher IOP increase and significantly more IOP spikes than Healon5 in the early period after small incision cataract surgery.

Silicone intraocular lens implantation in children: preliminary results

PurposeTo evaluate the safety and outcome of foldable silicone intraocular lens (IOL) implantation in children. SettingDepartment of Ophthalmology, University of Giessen, Giessen, Germany. MethodsThe results of cataract extraction and silicone IOL implantation in children having surgery between 1992 and 1997 were retrospectively analyzed in 8 eyes (7 patients). All IOLs were implanted in the capsular bag through a 3.5 mm clear corneal incision. In 4 eyes, primary posterior capsulectomy and anterior vitrectomy were performed. ResultsMean patient age at the time of surgery was 5.1 years (range 8 months to 15 years). The surgeries were uneventful. All IOLs remained anatomically stable and well centered during the mean follow-up of 29.6 months (range 18 to 46 months). Postoperative inflammatory reaction was minimal. Neither fibrinoid exudation nor posterior synechias occurred postoperatively. Postoperative best spectacle-corrected visual acuity ranged from 20/800 to 20/20. All eyes with an intact posterior capsule developed posterior capsule opacification. In the 4 eyes that had primary posterior capsulectomy and anterior vitrectomy, the visual axis remained clear. ConclusionsThese preliminary results suggest that silicone IOL implantation in children is a safe procedure with good and stable short-term anatomic results. Longer follow-up is necessary to answer questions about the long-term safety of silicone lens implantation in a child’s eye.

Late pigmented-membrane formation on silicone intraocular lenses after phacoemulsification with or without trabeculectomy

Purpose To determine the incidence of late inflammatory membrane formation with pigment precipitates on foldable silicone or poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) after phacoemulsification with or without simultaneous trabeculectomy and to identify probable causative factors. Setting Eye Department, Bnai–Zion Medical Center, and the Faculty of Medicine, the Technion, Haifa, Israel. Methods In this retrospective study, 155 eyes (140 patients) were divided into 4 groups by the surgery performed: Group 1, phacoemulsification combined with trabeculectomy and foldable silicone IOL implantation (12 eyes); Group 2, phacoemulsification combined with trabeculectomy and PMMA IOL implantation (15 eyes); Group 3, phacoemulsification alone with foldable silicone IOL implantation (66 eyes); Group 4, phacoemulsification alone with PMMA IOL implantation (62 eyes). Preoperative, intraoperative, and postoperative data were compared. Results Late inflammatory membranes were found on the anterior surface of 33% of the IOLs in Group 1, 3% in Group 3, and none in Groups 2 and 4. Membranes developed 3 to 4 months after surgery, were resistant to topical corticosteroid treatment, and required repeated neodymium:YAG laser treatments. No correlation with preoperative, intraoperative, or postoperative factors was found. Conclusion Foldable silicone IOLs may induce late postoperative inflammatory membranes with pigment precipitates, especially after combined phacoemulsification and trabeculectomy.

Corneal shape changes after temporal and superolateral 3.0 mm clear corneal incisions

Purpose To compare the corneal topographic changes after temporal and superolateral 3.0 mm clear corneal incisions (CCIs) and implantation of foldable silicone intraocular lenses (IOLs). Setting Department of Ophthalmology, University of Vienna, Austria, and a private clinic, Winterthur, Switzerland. Methods This prospective study comprised 54 eyes of 54 patients scheduled for cataract surgery. After a 0.3 mm deep precut, a temporal 3.0 mm CCI was made in 26 eyes and a superolateral (at 10:30) 3.0 mm CCI in 28 eyes. Corneal topography was recorded preoperatively and 1 week and 1 and 3 months postoperatively using the TMS-1 computer-assisted videokeratoscope (Computed Anatomy, Inc.). Surgically induced corneal shape changes were evaluated by batch-by-batch analyses of the paired differences between the records. The significance of topographic changes was calculated by the paired Wilcoxon test; group comparisons were made using the Wilcoxon group comparison test. Results Both groups had incision-related corneal flattening at 1 week and 1 and 3 months postoperatively. The extent of this flattening at 1 week and 1 and 3 months postoperatively was up to 1.0, 0.9, and 0.7 diopter (D), respectively, in the temporal group and up to 1.2 D at each observation time in the superolateral group. There was statistically significantly more incision-related corneal flattening in the superolateral incision group than in the temporal incision group; the difference was up to 0.3 D after 1 month and 0.5 D after 3 months. Conclusion The superolateral incision induced statistically significantly more incision-related corneal flattening than the temporal incision.

Transscleral fixation of foldable intraocular lens after pars plana lensectomy in eyes with a subluxated lens

Two patients had a subluxated crystalline lens: one with Marfan’s syndrome and the other with traumatic cataract. A pars plana lensectomy with transscleral fixation of a foldable silicone intraocular lens rather than a conventional poly(methyl methacrylate) lens was performed. Excellent, rapid visual rehabilitation was obtained using this small incision technique.

A randomized clinical trial of combined topical-intracameral anesthesia in cataract surgery

Objective To evaluate the level of patient discomfort during phacoemulsification and implantation of a foldable intraocular lens (IOL) while under topical lidocaine, alone or in combination with intracameral lidocaine. Design A prospective, randomized, controlled trial. Participants Between January and July 1997, a total of 162 patients (162 eyes) scheduled for cataract surgery were randomly assigned to either the placebo group (topical anesthesia with intracameral balanced salt solution [group 1, n = 81]) or the interventional group (combined topical-intracameral anesthesia [group 2, n = 81]). Interventions All patients underwent temporal clear corneal phacoemulsification and implantation of a foldable silicone IOL. All patients received a minimum total of five doses (two drops per dose) of 2% topical lidocaine hydrochloride. Three doses were administered before surgery into the superior and inferior cul-de-sac at 10 minutes, 5 minutes, and immediately before the initial corneal incision. One dose was administered before the commencement of phacoemulsification and another dose before implantation of the IOL. In addition, all patients received an intracameral injection immediately after entrance into the anterior chamber. Patients in group 1 received a 0.5-ml injection of balanced salt solution, and those in group 2 received a 0.5-ml injection of 1% lidocaine. Main outcome measure A 10-point visual analogue scale was used immediately after the surgery to assess each patient’s overall severity of pain intraoperatively. Results Ninety percent of patients in group 1 and 95% in group 2 assigned a score of 0 or 1 to the level of intraoperative discomfort. The mean pain score +/−1 standard deviation for group 1 was 0.63 ± 0.68 and for group 2 was 0.37 ± 0.58. The difference between the pain scores for the two groups was statistically significant ( P = 0.0053). A small but significant proportion (15%) of patients in group 1 expressed distress when the ciliary body was stretched or the iris was manipulated with instruments. Conclusion Although topical lidocaine alone provides adequate anesthesia for phacoemulsification and implantation of a foldable IOL, combined topical and intracameral administration of lidocaine can further minimize intraoperative discomfort.

Evaluation of a 3-piece silicone intraocular lens with poly(methyl methacrylate) haptics

Purpose: To evaluate the safety and performance of a foldable silicone intraocular lens (IOL) in small incision phacoemulsification surgery.Setting: Vaasa Central Hospital, Vaasa, Finland.Methods: Phacoemulsification with primary implantation of a posterior chamber IOL was performed in 50 patients. All eyes were implanted with a CeeOn™ IOL (model 920, Pharmacia & Upjohn) with a silicone optic and poly(methyl methacrylate) haptics. The ease of folding, implanting, and unfolding the IOL in the bag were recorded. Visual acuity, postoperative complications, optic;decentration, and optic tilt were measured at 5 postoperative visits. The IOLs were evaluated for haze and discoloration and the IOL surface, for inflammatory or pigment deposits. Follow-up was 12 months.Results: In 44 of 50 cases, folding the IOL was easy, and in 46 of 50, unfolding the IOL was controlled. The mean follow-up was 11.45 months ± 0.52 (SD), No postoperative complications occurred, and 96% of patients achieved a best corrected visual acuity (BCVA) of 0.5 or better and 56%, a BCVA of 1.0 or better. The IOL decentration was less than 0.25 mm in 89% of cases, and there was no optic tilt. The neodymium:YAG laser capsulotomy rate was 11%.Conclusion: Good visual outcome and excellent centration were achieved with the CeeCin model 920 IOL. It is therefore suitable for small incision cataract surgery. Because of the IOLs smooth, polished surface, the choice of instruments for folding and implantation is important.

Posterior continuous curvilinear capsulorhexis and postoperative inflammation

Purpose: To evaluate the influence of posterior continuous curvilinear capsulorhexis (PCCC) on inflammation after phacoemulsification and implantation of a foldable silicone intraocular lens (IOL) in the capsular bag.Setting: St. Erik's Eye Hospital, Stockholm, Sweden.Methods: Fifty patients were enrolled in this prospective, randomized study. Eyes with diabetes mellitus, glaucoma, uveitis, exfoliation syndrome, other previous ocular diseases, or an axial length greater than 26.0 mm were excluded. One group comprised 25 eyes of 25 patients (median age 76 years) in which phacoemulsification and implantation of a silicone IOL in the capsular bag were performed. The other group consisted of 25 eyes of 25 patients (median age 77 years) who received the same surgical procedure in addition to PCCC. The aqueous protein concentration was measured using a laser flare meter (FC 500, Kowa Co.) preoperatively and 1 day, 1 week, and 1 and 3 months after surgery.Results: Surgical trauma significantly increased aqueous flare values 1 day, 1 week, and 1 month after surgery in both groups (P < .05). Three months postoperatively, flare values in both groups were not different from preoperative values. No difference between the 2 groups was found in flare intensity measurements or in best corrected visual acuity before and after uneventful surgery. The incidence of postoperative clinical cystoid macular edema was 8% (2 eyes) in the control group and 4% (1 eye) in the group with PCCC.Conclusion: Postoperative flare intensity after phacoemulsification with PCCC and implantation of a foldable silicone IOL was not significantly different than postoperative flare measurements in a control group.

Anterior capsule contraction with foldable silicone intraocular lenses

Purpose: To examine the causes, signs, and symptoms of anterior capsule contraction syndrome and the response to neodymium:YAG (Nd:YAG) anterior capsulotomy.Setting: Madigan Army Medical Center, Tacoma, Washington, USA.Methods: This retrospective review comprised 70 cases of phacoemulsification with foldable plate-haptic silicone intraocular lens (IOL) implantation. Patients who developed anterior capsule contraction postoperatively, defined as the anterior capsule being visible through an undilated pupil, had a radial anterior capsulotomy with an Nd:YAG laser. Variables analyzed were visual acuity, subjective complaints, associated inflammation, and IOL decentration.Results: Ten eyes of 9 patients (14%) developed anterior capsule contraction and had Nd:YAG laser radial anterior capsulotomy. Three of 9 patients reported decreased visual acuity and glare. Two other patients had chronic anterior_ chamber inflammation unresponsive to steroids after surgery that resolved after Nd:YAG anterior capsulotomy. Intraocular lens decentration was observed in 3 patients before the Nd:YAG capsulotomy. Posterior lens dislocation occurred in 1 patient after capsulotomy and required surgical lens exchange.Conclusion: One-piece foldable silicone IOLs may not provide enough peripheral capsule expansion.

Cartridge cracks during foldable intraocular lens insertion

Purpose: To assess the incidence of cartridge cracks during foldable intraocular lens (IOL) insertion and to determine factors that play a role in the development of these cracks.Setting: Leesburg Regional Ambulatory Surgical Care Center, Leesburg, Florida, USA.Methods: Small incision cataract surgery was performed in 350 consecutive cases. A foldable silicone IOL (Allergan Medical Optics SI-40) was inserted in all cases using the Unfolder- cartridge and 3 viscoelastic agents: sodium hyaluronate (Healon®, Vitrax®) and sodium chondroitin sulfate-sodium hyaluronate (Viscoat®).Results: Cartridge cracks occurred in 52 eyes (14.86%). Almost all cracks (98.1%) occurred in cases in which Healon was used to load the IOL. In each case of a cracked cartridge, there was evidence of the plunger overriding the optic edge.Conclusions: We recommend the use of chondroitin-based viscoelastic agents to load the SI-40 foldable IOL to minimize the risk of cartridge cracks. Modifications in the design of the IOL inserter may eliminate the problem of cartridge cracks.

Intraocular Pressure Changes after Phacoemulsification and Foldable Silicone Lens Implantation Using Healon GV®

The authors studied the intraocular pressure (IOP) changes after phacoemulsification with two different kinds of foldable silicone lens implantation using Healon GV® as viscoelastic substance. One hundred patients undergoing cataract surgery were enrolled in this study. Inclusion criteria were: absence of ocular hypertension or glaucoma. Patients were randomly assigned to plate haptic (Silens PH®, Domilens® Chiron Vision, Lyon, France) or three-piece (CeeOn™& ;920, Pharmacia spa, Milano, Italia) silicone intraocular lens (IOL) implantation. Following phacoemulsification and cortical aspiration, the capsular bag was reinflated with Healon GV. After foldable silicone IOL insertion residual Healon GV was removed from the anterior chamber. IOP was measured preoperatively and at 6, 24 h and 1 week postoperatively. Six hours postoperatively IOP was higher in the Silens PH group than in the CeeOn group (20.85±5.42 vs. 18.88±2.95 mm Hg, p = 0.026). The difference was confirmed after 24 h (21.02±5.18 vs. 17.34±3.18 mm Hg, p < 0.01). Despite the medical treatment (acetazolamide 250 mg orally every 6 h), at the 24-hour control 2 eyes with plate haptic silicone lens showed IOP values higher than 30 mm Hg. Slitlamp examination showed in both eyes a shallowing of the anterior chamber together with the evidence of capsular bag hyperdistension and capsular block resulting from the occlusion of the circular anterior capsule opening by the plate haptic IOL. Residual Healon GV removal from the anterior chamber was performed. At 1-week control both eyes showed normalization of IOP. The use of a plate haptic silicone lens may be associated with a more consistent retention of Healon GV in the eye with trapping in the capsular bag. Retained viscoelastic may cause either trabecular meshwork blockage by viscoelastic substance or postoperative capsular bag hyperdistension, anteroplacement of the IOL optic and capsular block from occlusion of the circular anterior opening by the IOL optic.

Effect of heparin in irrigating solution on inflammation following small incision cataract surgery

Purpose: To study the effect of heparin-sodium added to the irrigating solution on postoperative inflammation in patients having cataract surgery.Setting: Department of Ophthalmology, University of Giessen, Giessen, Germany.Methods: Seventy-two patients having phacoemulsification with posterior chamber intraocular lens (IOL) implantation were randomly assigned to receive regular irrigating solution or solution with heparin-sodium (final diluted concentration 10 IU/mL). In half the patients, poly(methyi methacrylate) (PMMA) IOLs were implanted and in half, foldable silicone IOLs. The patients were examined preoperatively, on days 1 and 3, and 1 year postoperatively. Postoperative inflammation was objectively evaluated by measurement of flare and cells using laser flare-cell photometry.Results: The mean postoperative flare values were significantly lower in the groups with additional heparin-sodium at days 1 and 3 (P < .01). Flare values were not significantly different 1 year postoperatively. Cell values for the heparin-treated groups were lower, but the difference did not reach statistical significance. Flare and cells values for the two IOL materials were not significantly different during the entire follow-up.Conclusion: Heparin-sodium added to the infusion solution during small incision cataract surgery reduced inflammation in the early postoperative period.

Deposition of extracellular matrix on silicone intraocular lens implants in rabbits.

To examine the deposition of extracellular matrix on silicone intraocular lenses (IOLs) implanted experimentally into rabbit eyes by electron microscopy and to determine the immunolocalization of extracellular matrix components, including collagen types and cellular fibronectin, on these IOLs. We performed phacoemulsification and aspiration of the crystalline lens and implanted a foldable silicone IOL in the capsular bag of one eye of each of 26 adult albino rabbits under general anesthesia. After 8 weeks the animals were killed and the eyes were enucleated. The silicone IOLs were processed for electron microscopy and for immunohistochemical detection of collagen types I, III, and IV and cellular fibronectin. Electron microscopy revealed deposition of a presumed cell matrix complex on the optic portion of all silicone IOLs, as well as the adhesion of presumed macrophages and foreign-body giant cells. Cellular deposits showed immunoreactivity for cellular fibronectin. Fibrous or membranous deposits exhibited immunoreactivity for cellular fibronectin and collagen types I and III. A few type IV collagen-immunoreactive deposits were also seen. Deposits of extracellular matrix components were observed on silicone IOLs. These deposits may form the scaffolding for the adhesion and proliferation of cells. These matrix components appeared to be the products of cells adhering to the surfaces of IOLs, including lens epithelial cells, macrophages and foreign-body giant cells, indicating that the process of granulation was incomplete.

Comparative study of intraocular lens implantation through 3.0 mm temporal clear corneal and superior scleral tunnel self-sealing incisions

Purpose: To compare the clinical outcome of phacoemulsification and foldable silicone intraocular lens (IOL) implantation through a 3.0 mm temporal clear corneal incision and a 3.0 mm superior scleral tunnel incision.Setting: Department of Ophthalmology, Yodogawa Christian Hospital, Osaka, Japan.Methods: Eighty cataractous eyes of 78 patients with pre-existing against-the-rule (ATR) astigmatism were recruited for this prospective, randomized study. The patients were assigned to one of the two groups. Data on uncorrected and corrected visual acuities, keratometry, flare intensity measurement, and central cornea endothelial cell count were evaluated preoperatively and at 2 days, 1 week, and 1 and 3 months postoperatively.Results: Although the pre-existing keratometric cylinder decreased in the temporal clear corneal incision group and increased in the superior scleral tunnel incision group, the amount of cylinder shift was not significantly different. Mean scalar shift of keratometric cylinder in the corneal incision group was 1.19 diopters (D) at 2 days postoperatively, 0.86 D at 1 week, and 0.56 D at 3 months and in the scleral incision group, 1.09 D at 2 days, 0.76 D at 1 week, and 0.65 D at 3 months. Eighty percent of the eyes in each group achieved an uncorrected visual acuity of 20/40 or better from the second day postoperatively. No statistically significant difference in visual rehabilitation or other parameters was noted between the groups throughout the study. Complications including corneal endothelial cell loss and wound incompetence requiring suturing were observed in the temporal clear corneal incision group.Conclusions: Both incisions offered satisfactory clinical results, but the superior scleral tunnel incision resulted in fewer complications. Minimal corneal keratometric change induced by a 3.0 mm incision was not related to uncorrected visual rehabilitation.