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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.

Results of hydrophilic acrylic, hydrophobic acrylic, and silicone intraocular lenses in uveitic eyes with cataract : comparison to a control group

Purpose: To evaluate the uveal and capsular biocompatibility of hydrophilic acrylic, hydrophobic acrylic, and silicone intraocular lenses (IOLs) in eyes with uveitis. Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: This prospective study comprised 72 eyes with uveitis and 68 control eyes having phacoemulsification and IOL implantation by 1 surgeon. Patients received 1 of the following IOLs: foldable hydrophilic acrylic (Hydroview®, Bausch & Lomb), hydrophobic acrylic (AcrySof®, Alcon), or silicone (CeeOn® 911, Pharmacia). Postoperative evaluations were at 1, 3, and 7 days and 1, 3, and 6 months. Cell reaction was evaluated by specular microscopy of the anterior IOL surface and the anterior and posterior capsule reaction, by biomicroscopy. Results: Small round cell deposition was observed on all IOLs in the immediate postoperative period, especially in eyes with uveitis. This reaction decreased 3 to 6 months after surgery. Although the CeeOn 911 had a higher mean grade of small cells, there was no statistical difference between the 3 IOL types after 6 months in the uveitis and control groups. Foreign‐body giant cells (FBGCs) increased after 1 week to 1 month. The AcrySof IOLs had the highest number of FBGCs; after 6 months, there was a statistically significant difference between the AcrySof and Hydroview uveitis groups (P = .036) and the AcrySof and CeeOn 911 uveitis groups (P = .003) but there was no difference among the 3 IOL types in the control group. Lens epithelial cell outgrowth persisted on the Hydroview IOLs in control eyes and regressed on all 3 IOL types in uveitic eyes and on the AcrySof and CeeOn 911 IOLs in control eyes (P = .0001). Anterior capsule opacification (ACO) was more severe on all IOL types in uveitic eyes and on the CeeOn 911 IOL in control eyes. Posterior capsule opacification (PCO) was more severe in uveitic eyes. The Hydroview group had more severe PCO than the AcrySof and the CeeOn 911 groups in uveitis and control eyes. Six months postoperatively, the difference was significant (P = .0001). There was no significant difference between the AcrySof and CeeOn 911 IOLs. Conclusions: Intraocular lens biocompatibility is inversely related to inflammation. Hydrophilic acrylic material had good uveal but worse capsular biocompatibility. Hydrophobic acrylic material had lower uveal but better capsular biocompatibility. Silicone showed a higher small cell count (mild) and more severe ACO but achieved PCO results comparable to FBGC results and better than those with the AcrySof lens 6 months after surgery. Despite the differences in IOL biocompatibility, all patients benefited from the surgery.

Two year results: sharp versus rounded optic edges on silicone lenses.

Purpose: To evaluate the role of optic edge design of 2 silicone intraocular lenses (IOLs) in 2 year clinical results. Setting: Department of Ophthalmology, University of Vienna, Medical School, Allgemeines Krankenhaus, Austria. Methods: In this comparative clinical study, 50 eyes had phacoemulsification and implantation of a high‐refractive 3‐piece silicone IOL with sharp optic edges (CeeOn™ model 911F) (n = 25) or a 3‐piece silicone lens with rounded optic edges (CeeOn™ model 920) (n = 25). Biomicroscopic findings, including those of specular microscopic examination of the anterior lens surface, were documented and the results analyzed. Results: After 2 years, a significant between‐group difference in posterior capsule opacification (PCO) but not in anterior capsule alterations was observed. Behind all CeeOn 911F sharp‐edge IOLs, the capsule remained clear; in 2 of 23 capsules behind the CeeOn 920 rounded‐edge, a neodymium: YAG laser capsulotomy had to be performed for dense central fibrotic PCO. Seven of 21 of the remaining eyes had first‐degree central fibrotic PCO, 14 of 23 had peripheral mixed fibrotic and slender Elschnig pearl PCO, and 8 of 23 had second‐degree peripheral PCO. Specular microscopic findings did not differ between the 2 groups. No severe IOL decentration occurred in any eye; 25% in the sharp‐edge group and 40% in the rounded‐edge group had minimal decentration. Conclusion: The silicone IOL with the sharp optic edge design was associated with significantly reduced PCO 2 years postoperatively.

Influence of operator experience on the performance of ultrasound biometry compared to optical biometry before cataract surgery

Purpose: To compare measurements performed with the IOLMaster (Carl Zeiss, Meditec AG) with those obtained by applanation ultrasound (US) and manual keratometry and to evaluate the effect of operator experience on US biometry. Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: The axial length (696 eyes) and anterior chamber depth (ACD) (462 eyes) were measured in 377 patients with cataract using the IOLMaster and applanation US. To assess the effect of operator experience on the biometric results, the operators were divided into 2 groups: experienced and less experienced in performing US biometry. The difference in measurements between the methods and the variability of the difference were compared between the 2 groups. Results: Applanation US measured axial length and ACD shorter than the IOLMaster; the mean numerical difference was 0.13 mm and 0.19 mm, respectively (P<.01). For axial length, the absolute difference was smaller with experienced operators than with less experienced operators (0.15 mm versus 0.22 mm) (P<.01). For ACD, experienced operators obtained a smaller difference between measurement techniques (0.21 mm versus 0.29 mm; P<.05). Conclusions: Experienced US operators had less difference and lower variability in the difference between applanation US and IOLMaster readings for axial length and ACD measurements. The noncontact optical method, which is essentially operator independent, gave significantly more reliable biometry before cataract surgery, especially in the case of less experienced operators.

Comparison of the biocompatibility of 2 foldable intraocular lenses with sharp optic edges.

Purpose: To compare the clinical performance of 2 foldable intraocular lenses (IOLs) with sharp optic edges in terms of uveal and capsular biocompatibility. Setting: Department of Ophthalmology, University Hospital of Vienna, Vienna, Austria. Methods: Fifty eyes scheduled for cataract surgery were included in this comparative study. A standardized surgical protocol was used, and all operations were performed by 1 experienced surgeon. Two posterior chamber lens types of similar design with a 6.0 mm sharp‐edged optic and poly(methyl methacrylate) haptics were used. Twenty‐five eyes received an AcrySof® acrylic IOL (Alcon), and 25 eyes received a CeeOn® 911A® silicone IOL (Pharmacia). Relevant data were collected at a 3‐year follow‐up examination. To evaluate uveal biocompatibility, anterior chamber laser flare and cell measurements and inflammatory cell reactions were monitored. Cellular biocompatibility was investigated by examining anterior capsule opacification (ACO), posterior capsule opacification (PCO), and lens epithelial cell (LEC) ongrowth on the IOLs anterior surface. Factors such as intralenticular glistenings and IOL decentration were also evaluated. Results: Anterior chamber flare and cells and the inflammatory cell reaction were significantly lower in the CeeOn 911A group. There was no statistically significant difference in ACO, PCO, and LEC ongrowth between the 2 groups. The AcrySof lenses showed significantly better centration and a higher density of intralenticular glistening. Conclusions: The findings show that a sharp‐edged optic design is, to date, the most effective method of reducing the rate of PCO. Despite a subclinical foreign‐body reaction in the AcrySof group, both lenses had a high degree of capsular and uveal biocompatibility.

Uveal and capsular biocompatibility of 2 foldable acrylic intraocular lenses in patients with uveitis or pseudoexfoliation syndrome: comparison to a control group.

Purpose: To evaluate the uveal and capsular biocompatibility of hydrophilic acrylic (Hydroview®) and hydrophobic acrylic (AcrySof®) intraocular lenses (IOLs) after phacoemulsification in eyes with pseudoexfoliation syndrome (PEX) or uveitis and compare the results with those in a control group. Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: This prospective nonrandomized comparative trial comprised 143 eyes recruited consecutively. Of these, 49 eyes had PEX, 43 had uveitis, and 51 served as controls. A standardized surgical protocol was used. Cell reaction, anterior (ACO) and posterior (PCO) capsule opacification, and flare were evaluated 1 year after cataract surgery. Results: Regarding uveal biocompatibility, the number of foreign‐body giant cells (FBGCs) increased in proportion to associated ocular pathologies in both IOL groups. The difference between the Hydroview control and Hydroview uveitis groups was statistically significant. The number of FBGCs was greater on AcrySof IOLs than on Hydroview IOLs in all 3 groups. The difference in FBGCs between the 2 IOL types was statistically significant in the control and PEX groups. Regarding capsular biocompatibility, lens epithelial cell (LEC) outgrowth was inversely correlated with intraocular inflammation. Outgrowth was statistically significantly higher with Hydroview IOLs, occurring in 85% in the control group, 45% in the PEX group, and 28% in the uveitis group (P < .0001). With AcrySof lenses, the percentages were 0%, 8%, and 4%, respectively. The PEX and uveitis groups were more likely to develop ACO than the control group (P < .012). There was no statistically significant difference in ACO between the 2 IOL types in the 3 patient groups. The PCO was statistically significantly greater in the uveitis group than in the control group (P < .026) and statistically significantly more dense on Hydroview than on AcrySof IOLs in all 3 patient groups (P < .002). Flare was statistically significantly higher in the uveitis group than in the PEX and control groups with both IOL types (P < .012). There was no statistically significant difference in flare between the 2 IOL types. Conclusions: Uveal and capsular biocompatibility depends on the intensity of ocular inflammation. The greater the inflammation, the less the biocompatibility of hydrophilic and hydrophobic acrylic materials. AcrySof stimulated more FBGCs. The Hydroview material had better uveal but poorer capsular biocompatibility than AcrySof. The sharp optic edge effect of the AcrySof IOL and the advantages of the Hydroview lens in normal eyes are less apparent in compromised eyes.

Lens epithelial cell outgrowth on 3 types of intraocular lenses

Purpose: To compare the outgrowth of lens epithelial cells (LECs) on 3 types of intraocular lenses (IOLs) to determine the influence of lens material and lens design (optic edge) on this phenomenon. Setting: Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria. Method: Ninety eyes scheduled for cataract surgery were included in a prospective comparative study. A standardized surgical procedure was performed by 1 experienced surgeon. Patients received 1 of 3 types of posterior chamber IOLs of similar design with a 6.0 mm optic and poly(methyl methacrylate) haptic: AcrySof® (Alcon), HydroView™ (Bausch & Lomb), or Sensar™ (Allergan). Each IOL type was implanted in 30 eyes. Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, and 180 days and 1 year after surgery. Lens epithelial cells in each quadrant of the anterior lens surface were subjectively graded. The product with the highest density and the number of quadrants with this density were used to measure LEC outgrowth. Results: Statistically significant differences (P < .05) were seen between the hydrophilic IOL and the 2 hydrophobic lenses from day 30 until the final examination. The HydroView lens had a higher number of LECs on its anterior surface than the AcrySof or Sensar IOL. There were no statistically significant differences between the 2 acrylic IOLs at any measurement. Conclusion: The findings suggest that lens surface properties have a greater influence on LEC outgrowth than lens design (ie, sharp optic edge).

Influence of viscoelastic substances used in cataract surgery on corneal metabolism and endothelial morphology: Comparison of Healon and Viscoat

Purpose: To evaluate the influence of cohesive and dispersive ophthalmic viscosurgical devices (OVDs) on endothelial morphology and corneal metabolism during cataract surgery. Setting: Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria. Methods: In this prospective randomized blind study, 50 eyes of 43 patients were randomized into 2 groups before surgery. Phacoemulsification with implantation of a posterior chamber intraocular lens was performed in all patients. In half the patients, sodium hyaluronate 1% (Healon®) was used as the OVD and in the other half, sodium hyaluronate 3%‐chondroitin sulfate 4% (Viscoat®). Corneal metabolism was evaluated by fluorophotometric measurement of corneal autofluorescence. The corneal fluorescence values were corrected for interference by fluorescence of the ocular lens. Specular microscopy (Noncon Robo SP800, Canon) was used to evaluate the endothelial cell density, coefficient of variation, and percentage of hexagonal cells. Examinations were performed preoperatively and 3 days, 1 and 4 weeks, and 3 months postoperatively. Results: There were no significant changes between preoperative and postoperative endothelial cell density measurements in either group (P = .1717). The percentage of hexagonal cells was similar (P = .3489); however, there was a slightly increasing tendency toward polymorphism in both groups. Corneal autofluorescence decreased 3 days after surgery, increased after 1 week, and decreased again subsequently in both groups. There was no significant difference in the influence on corneal metabolism between the 2 OVDs (P = .9899). Conclusions: There was no significant difference between Healon and Viscoat. Thus, this study did not confirm an advantage of either for endothelial protection of healthy corneas.

The clinical use of viscoelastic artificial tears and sodium chloride in dry-eye syndrome.

This study was performed to test viscoelastic artificial tears (VAT) based on both subjective and clinical parameters in patients with keratoconjunctivitis sicca (KCS). Twenty-eight patients were evaluated in a randomized double-blind study. Sodium hyaluronate was used in two different concentrations (0.4%, 0.25%) and in combination with chondroitin sulfate. Each preparation was used for one week preceded by another weekly cycle using a sodium chloride solution. Before and after each cycle, clinical examinations were performed: tear film break-up time, Schirmers test, lipid-layer thickness and fluorescein staining. Patients kept a record of the drop-frequency, subjective response and side effects. After the study, they were asked to give a rating of the various preparations. The severity of KCS was expressed based on a sicca score and correlated with response to viscoelastic treatment. Both the subjective and the clinical parameters revealed no statistically significant differences between the various viscoelastic agents or between the viscoelastics and the sodium chloride solutions. Severe side effects did not occur. There was a positive correlation of response to viscoelastic treatment with severe KCS (+ 0.36) but not with mild KCS (-0.07). The VAT seems to be indicated in severe cases of dry-eye syndrome. Sodium chloride solutions may be a useful short-term alternative to other tear formulations.

Effect of heparin in the irrigation solution on postoperative inflammation and cellular reaction on the intraocular lens surface

Purpose: To evaluate the influence of heparin sodium in the irrigation solution on postoperative inflammation and cellular reaction on the anterior surface of a hydrophilic intraocular lens (IOL). Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: This randomized prospective single‐surgeon study included 50 patients with senile cataract only. Half the patients received 1 mL of heparin sodium (concentration 10 IU/mL) in addition to the regular irrigating solution. In all other respects, the procedure was standardized: clear corneal incision, phacoemulsification, and implantation of a Hydroview® foldable hydrogel IOL (Bausch & Lomb). The parameters of inflammation—anterior chamber flare and cells—were evaluated with the pupil dilated in a masked fashion using a Kowa FC‐1000 laser flare‐cell meter 1, 3, 7, 14, and 28 days and 3, 6 and 12 months postoperatively. The cellular reaction was semiquantitatively examined and analyzed by specular microscopy. Results: In both groups, flare and cell values increased on the first postoperative day and successively decreased thereafter. In the first week, the flare and cell values were significantly higher in the group without heparin sodium in the irrigating solution. Subsequently, there were no differences between the 2 groups in flare or cells. At 1 day, the heparin sodium group had statistically significantly fewer IOLs with no cells on the surface. Subsequently, no differences in cellular reaction on the IOL were observed. Conclusions: Heparin sodium added to the standard irrigating solution reduced disturbances of the blood‐aqueous barrier in the early postoperative period. There seemed to be no long‐term effect, especially on cellular reaction, on the hydrophilic IOL surface.