Nd:YAG capsulotomy rates after use of the AcrySof acrylic three piece and one piece intraocular lenses

BACKGROUND/AIM: Acrylic lens size and shape may influence the rate of posterior capsule opacification (PCO) and need for Nd:YAG capsulotomy. The aim of this study is to compare the Nd:YAG capsulotomy rate of the three piece acrylic/PMMA AcrySof MA series lens with the one piece acrylic AcrySof SA series lens. METHODS: 434 eyes of 329 patients who had cataract extraction and implantation of one of four types of intraocular lenses (IOLs) were evaluated for rate of Nd:YAG capsulotomy. 176 eyes received the acrylic AcrySof MA30AC IOL, 71 eyes the acrylic AcrySof MA60AC IOL, 45 eyes the acrylic AcrySof SA30AL IOL, and 142 eyes the acrylic AcrySof SA60AT IOL. RESULTS: The rates of Nd:YAG capsulotomy with the three piece IOL (MA30AC/MA60AC) and the one piece IOL (SA30AL/SA60AT) were 1.2% and 2.1% at 6 months, 2.8% and 5.9% at 12 months, and 3.6% and 7.5% at 24 months, respectively. The incidence of Nd:YAG capsulotomy was higher in patients who received the one piece IOL (p=0.01, log rank test). There was no difference in Nd:YAG capsulotomy rates when comparing lens optic size, age, sex, history of pars plana vitrectomy, and diabetes mellitus. CONCLUSIONS: This study shows a greater incidence of Nd:YAG capsulotomy in patients who receive one piece acrylic AcrySof lenses when compared to those who receive three piece acrylic AcrySof lenses.     

Optical resolution of foldable intraocular lenses

Recently manufactured intraocular lenses (IOLs) (STAAR AA 4203 made of silicone and IOGEL PC-12 made of polyHEMA) were tested before and after implantation simulation for axial optical resolution (model eye), for optical surface quality (photokeratoscope), and for surface microtrauma (scanning electron microscopy). At a 3 mm pupillary opening, both lens types achieved a mean axial resolution of 1.25 (range 1.0 to 1.5) on an optotype analogous resolution target. When the pupillary opening was increased to 6 mm, polymacon IOLs showed only a moderate resolution decrease (up to one line) and loss of contrast (up to 30%); silicone IOLs showed almost no decrease. Photokeratoscopic evaluation revealed that a circular optical nonhomogeneity at the peripheral optical zone of the hydrogel IOLs is the source of this impairment. Groove-like surface deformities occasionally observed by scanning electron microscopy did not detectably decrease resolution or contrast.     

不同材料的折叠式人工晶状体植入的对比研究

目的 对比国产硅凝胶和进口丙烯酸酯折叠式人工晶状体的效果。方法 100眼白内障患者随机分为两组。白内障超声乳化后囊连续环形撕囊术（PCCC）后Ⅰ组植入国产硅凝胶折叠式人工晶状体,Ⅱ组植入丙烯酸酯（acrysof)折叠式人工晶状体。对术后视力、术后反应及并发症进行观察。结果 术后1天裸眼或矫正视力≥0．5者,Ⅰ组78％、Ⅱ组76％。术后1年裸眼或矫正视力≥1．0者,Ⅰ组72％,Ⅱ组78％,两组统计学上差异无显著性意义（P＞0．05）。术后前房炎症反应、玻璃体浑浊、角膜水肿及囊样黄斑水肿等并发症,两组间统计学上差异均无显著性意义（P＞0．05）。结论 在白内障超声乳化PCCC的基础上,国产硅凝胶和进口丙烯酸酯（acrysof)折叠式人工晶状体疗效相近。     

Transscleral fixation of foldable intraocular lenses

PURPOSE: To report the results of transscleral implantation of foldable intraocular lenses (IOLs). SETTING: Department of Ophthalmology Dokuz Eylül University School of Medicine, Izmir, Turkey. METHODS: Twenty eyes of 20 patients had transscleral fixation of a foldable IOL combined with conventional 3-port pars plana vitrectomy or anterior vitrectomy. Twelve eyes had lens luxation, 8 traumatic and 4 idiopathic. Six eyes were aphakic, 3 after extracapsular cataract extraction and 3 as a result of complicated phacoemulsification. One patient with a mature cataract and pseudoexfoliation had a wide zonular dialysis during phacoemulsification. One patient had an opacified hydrophilic acrylic IOL. RESULTS: The mean age of the patients was 52.9 years (range 17 to 80 years). The mean preoperative best corrected visual acuity (BCVA) was 20/63 (range counting fingers to 20/25). The mean preoperative refraction was +10.8 diopters (D) (range +10 to +13 D) and the mean preoperative astigmatism, 1.8 D (range 1.0 to 5.5 D). Sixteen IOLs were hydrophobic acrylic, 14 of which were 3-piece AcrySof MA60BM (Alcon) and 2 of which were Sensar AR40 (Allergan). Four IOLs, all VisaAcryl(Staar), were hydrophilic acrylic. The mean power of the IOLs was +22.0 D (range 19.0 to 26.0 D). The mean follow-up was 12 months (range 1 to 18 months). The postoperative BCVA ranged between 20/100 and 20/20, and the mean postoperative astigmatism was 1.1 D (range 0.5 to 4.0 D) at the last follow-up visit. The difference was statistically significant (P<.05). Suture exposure and cystoid macular edema were the only complications, each occurring in 2 eyes. CONCLUSION: Transscleral fixation of foldable IOLs takes less time and results in fewer complications and better visual outcomes.     

Management of dislocated foldable intraocular lenses

BACKGROUND: Foldable intraocular lenses (IOLs) have replaced rigid IOLs as the standard for cataract surgery. As with their predecessors, some foldable IOLs manifest dislocation. The applicability of techniques developed for dislocated rigid IOLs to dislocated foldable IOLs has not been widely studied. PURPOSE: The purpose of this study was to evaluate the results of management techniques for dislocated foldable IOLs. DESIGN: Retrospective, interventional case study. RESULTS: Thirty-two eyes underwent repair including repositioning without scleral sutures (17 eyes), repositioning using scleral suture (8), and IOL exchange (7). IOL types included silicone plate IOLs (15 eyes), 3-piece acrylic IOLs (12), and others (5). The visual acuity outcomes and complication rates were similar for all IOL types and surgical techniques. CONCLUSION: With minimal modifications and a few important exceptions, previously reported techniques for management of dislocated IOLs, including repositioning with or without scleral suture fixation, may be applied effectively to many styles of foldable IOLs.     

Cost effectiveness of foldable multifocal intraocular lenses compared to foldable monofocal intraocular lenses for cataract surgery

AIM: To analyse the cost effectiveness of foldable monofocal intraocular lenses (IOLs) compared to foldable multifocal IOLs in cataract surgery alongside a prospective, multicentre randomised clinical trial (RCT). METHODS: Patients underwent cataract surgery with bilateral monofocal (n = 97) or multifocal (n = 93) IOL implantation. Cost data and patient preferences, using the visual analogue scale (VAS), the time trade-off (TTO), and the standard gamble (SG) technique were obtained preoperatively and postoperatively by structured interviews. The incremental costs (multifocal minus monofocal), mean costs per patient, and differences in preferences were computed. RESULTS: Mean costs for glasses per patient in the monofocal group were 41.67 and in the multifocal group 149.58. The difference in costs between the multifocal and monofocal group was -92.09 and was statistically significant (p = 0.008). No significant differences were found in total costs or in effectiveness between the monofocal and multifocal IOL group. CONCLUSION: The cost effectiveness of multifocal IOLs is reduced to a cost minimisation analysis, because of the inability to demonstrate significant differences in effects. The use of multifocal IOLs in cataract surgery resulted in a significant reduction in costs for patient's postoperative spectacles.     

Comparison of decentration and tilt between one piece and three piece polymethyl methacrylate intraocular lenses

BACKGROUND—The extent of the decentration and tilt was prospectively compared between one piece polymethyl methacrylate (PMMA) and three piece PMMA intraocular lenses (IOLs) which were implanted in the capsular bag after performing continuous curvilinear capsulorhexis.
METHODS—91 patients underwent a one piece PMMA IOL implantation in one eye as well as the implantation of the three piece PMMA IOL with polyvinylidene fluoride loops in the opposite eye. The length of the lens decentration and the angle of the tilt were quantitated using the anterior eye segment analysis system (EAS-1000) at 1 week as well as 1, 3, and 6 months postoperatively.
RESULTS—The mean length of the decentration in the one piece IOL was smaller than that in the three piece IOL at 1 week (p=0.0092), 1 month (p=0.0044), 3 months (p=0.0069), and 6 months (p=0.0010) postoperatively. However, no significant difference was found in the degree of the tilt between the two types of IOLs throughout the observation periods.
CONCLUSION—These results clarified that the one piece PMMA IOL with rigid PMMA haptics implanted in the capsular bag provides a better centration than the three piece PMMA IOL with flexible haptics, whereas the tilt was the same between the two types of IOLs.

Keywords: intraocular lens; decentration; tilt; continuous curvilinear capsulorhexis     

Uveal and capsular biocompatibility of two foldable acrylic intraocular lenses in patients with endogenous uveitis — a prospective randomized study

Background  To compare a hydrophobic and a hydrophilic acrylic single-piece intraocular lens (IOL) in uveitis patients with respect to biocompatibility and visual outcome. Methods  Prospective, randomized study in patients with noninfectious uveitis after phacoemulsification and implantation of either a hydrophobic AcrySof™ (group 1, n = 30) or a hydrophilic Akreos adapt™ (group 2, n = 30), sharp-edged acrylic IOL. The primary outcome was uveal biocompatibility, detected by giant-cell deposition, anterior chamber cell count and laserflare photometry over a 6-month follow-up period. Secondary outcome measures were capsular biocompatibility, as detected by posterior capsule opacification (PCO), lens epithelial cell outgrowth and Nd:YAG capsulotomies, and visual outcome. Results  The groups did not differ with respect to anatomic type of uveitis, immunosuppressive treatment, associated systemic disease, and intraoperative manipulation. The number of giant cells on the anterior IOL surface was higher in group 1 than in group 2 (p = 0.03). The number of anterior chamber cells, laser flare photometry levels, and uveitis reactivations after surgery did not differ between the groups. After 6 months, the number of patients with PCO development (p = 1.0) and Nd:YAG capsulotomies (p = 0.21), lens epithelial cell outgrowth, visual outcome and uveitis complications were comparable in both groups. Conclusions  Both of the acrylic IOLs used had good uveal and capsular biocompatibility, leading to significant improvement in BCVA in patients with noninfectious uveitis. No obvious differences were detected at 6 months with respect to uveal and capsular biocompatibility and visual outcome. The authors have no financial interest in any of the materials used in this study.     

A clinical comparison of single-piece and three-piece truncated hydrophobic acrylic intraocular lenses

PURPOSE: To determine the clinical differences between three-piece (3P) and single-piece (SP) truncated hydrophobic acrylic intraocular lenses (IOL). DESIGN: Retrospective cohort clinical study. METHODS: The setting was an academic clinical practice. The patient population consisted of subjects without confounding comorbidity that could effect central vision with at least 1-year follow-up after uncomplicated surgical placement of 3P or SP IOLs in the capsular bag and at least 20/25 best-corrected postoperative vision documented. Observation procedures were as follows: logarithm of the minimal angle of resolution (LogMAR) visual acuity (uncorrected and best corrected), digital retroillumination photographs to ascertain posterior capsular opacification (PCO), anterior capsular opacification (ACO), IOL centration, and refractive stability by comparing this refraction with the early postoperative refraction. Patients completed a dysphotopsia questionnaire. Main outcome measures were as follows: LogMAR visual acuity (uncorrected and best corrected), PCO, ACO, IOL centration, refractive stability, and dysphotopsia outcomes comparing 3P and SP. RESULTS: Seventy-five patients were enrolled (36 3P and 39 SP). Corrected and uncorrected visual acuity, refractive stability, and IOL centration were similar. Single piece truncated hydrophobic acrylic intraocular lenses had more PCO (P =.013), less ACO (P =.001), less central flash looking at a peripheral light (P =.044), and less unwanted images to the side of a light source (P =.025) . CONCLUSIONS: Although similar in centration and refractive stability, SP has more PCO, less ACO, and less dysphotopsia than 3P.     

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.     

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     

Visual performance: Comparison of foldable intraocular lenses

PURPOSE: To compare best distance visual acuity, color perception, and contrast sensitivity between eyes with an AcrySof Natural intraocular lens (IOL) (Alcon Laboratories Inc.) and fellow eye with an AcrySof IOL and to compare results in the IOL groups to those in normal, similarly aged patients with clear phakic eyes. SETTING: Sri Sankaradeva Nethralaya, Guwahati, India. METHODS: This prospective randomized parallel group single-center patient-masked examiner-masked study comprised 26 eyes of 13 healthy patients with bilateral age-related cataract. All patients had cataract surgery by phacoemulsification in both eyes; 1 eye received an AcrySof Natural IOL (SN60AT) and the fellow eye, an AcrySof (SA60AT) IOL. Final postoperative examination was performed at the end of 18 months. In addition to other findings, visual acuity, color perception, and contrast sensitivity were recorded. A group of normal, similarly aged phakic individuals with clear lenses was examined for contrast sensitivity. The records thus obtained were analyzed statistically. RESULTS: The AcrySof and AcrySof Natural IOL groups had a statistically significant improvement in visual acuity and color perception in comparison to preoperative status, and this was maintained until the last postoperative follow-up at 18 months. There was no statistically significant difference in the findings between the 2 IOL groups. The AcrySof and the AcrySof Natural IOL groups showed significant improvement in contrast sensitivity from the preoperative to the postoperative period (both P < .001). However, the AcrySof Natural IOL group was better than the AcrySof IOL group when each group was compared separately to similarly aged phakic individuals with clear lenses. CONCLUSIONS: Pseudophakia following AcrySof Natural SN60AT and AcrySof SA60AT IOL implantation led to equivalent visual acuity and color perception. But the contrast sensitivity in the AcrySof Natural group was better and near normal in reference to a healthy, age-matched control group.     

Treatment of keratoconus by toric foldable intraocular lenses

PURPOSE: To report on the correction of marked regular corneal astigmatism due to keratoconus by toric intraocular lenses (IOL). SETTING: University eye hospital. METHODS: A 66-year-old woman presented with cataract and unilateral keratoconus (keratometric readings: 50.2/41.3 diopters [D]). She underwent routine cataract surgery with implantation of a foldable posterior chamber toric IOL (refractive power: +10.0 D sphere/+12.0 D cylinder). A 68-year-old surgically aphakic woman presented with peripheral accentuated keratoconus with regular and stable corneal astigmatism (keratometric readings: 39.75/61.5 D). She underwent secondary implantation of a foldable toric IOL (refractive power: -9.0 D sphere/+30.0 D cylinder) into the ciliary sulcus. RESULTS: After a follow-up period of 4 months, visual acuity increased to 0.70 with a correction of +0.75 sphere -2.5 cylinder/84 degrees in Patient 1; after a follow-up period of 6 months, visual acuity increased to 0.60 with a correction of +1.0 -2.0/90 degrees in Patient 2. CONCLUSIONS: Foldable toric silicone IOL may be a surgical option in the management of regular marked corneal astigmatism caused by keratoconus.