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PubMed2001

Theoretical analysis of accommodation amplitude and ametropia correction by varying refractive index in Phaco-Ersatz.

Phaco-Ersatz is a surgical procedure for restoring accommodation in which the presbyopic crystalline lens is replaced by a flexible polymer gel in the lens capsule. We assessed the feasibility of simultaneously correcting ametropia while restoring accommodation using Phaco-Ersatz by utilizing polymer gel of the appropriate refractive index. Computation results using paraxial equations and ray tracing on two model eyes indicate that although this approach might be feasible for the hypermetrope, its usefulness for correcting myopia is limited, principally due to significant reductions in the resultant amplitude of accommodation.

Accommodation, Ocular↗
PubMed2003

Cataract surgery and silicone oil removal: visual outcome and complications in a combined vs. two step surgical approach.

PURPOSE: To compare visual outcome and complications of two surgical strategies for patients who needed cataract surgery and silicone oil removal. METHODS: A prospective, nonrandomized study was performed to compare two groups of patients who had cataract surgery and silicone oil removal from April 1998 to January 2002. From April 1998 to November 1999, patients had two surgical sessions with cataract surgery before silicone oil removal (Group 1), and from December 1999 to January 2002, patients underwent combined cataract surgery and silicone oil removal in a single session (Group 2). RESULTS: Thirty-five patients were included in each group. The postoperative visual acuity improved by at least two lines of Snellen in 13 patients (37.1%) in Group 1 and 15 (42.8%) patients in Group 2 (P=0.63). The mean visual improvement was 0.12 lines and 0.13 lines in groups 1 and 2 (P=0.62). Complications in groups 1 and 2 included transient intraocular pressure rise (25.7% versus 28.5%), retinal detachment (14.2% versus 11.4%), fibrin reaction (5.7% in both groups), and persistent intraocular pressure rise (2.8% in both groups). CONCLUSION: The visual outcome and complication rates were similar in both groups. Combined surgery offers the advantages of a single surgical event and a faster visual rehabilitation. We therefore suggest a surgical approach with combined cataract surgery and silicone oil removal in selected patients with a stable retinal situation.

Capsulorhexis↗
PubMed2003

Topical versus peribulbar anaesthesia for cataract surgery.

BACKGROUND: To assess and compare the efficacy and safety of topical versus peribulbar anaesthesia in patients undergoing routine cataract surgery. METHODS: The unicentre, prospective, randomized, clinical interventional trial included 140 consecutive patients undergoing routine cataract surgery performed by one of two surgeons. The patients were randomly distributed to either peribulbar anaesthesia or topical anaesthesia. To assess intraoperative pain, each patient was asked immediately after surgery to quantitate his/her pain using a 10-point pain rating scale. RESULTS: The study groups did not differ significantly in pain score (p=0.54), duration of surgery (p=0.52), anaesthesia-related intraoperative difficulties (p=0.17), postoperative visual acuity (p=0.94), overall intraoperative surgical complication rate, blood pressure rise (p=0.16) or blood oxygen saturation (p=0.74) CONCLUSIONS: Patient comfort and surgery-related complications did not differ between topical anaesthesia and peribulbar anaesthesia. As there are no significant differences between the two techniques in terms of subjective pain experienced by patients, intraoperative complications and postoperative visual outcome, and in view of the minimally invasive character of topical anaesthesia compared to peribulbar anaesthesia, the present study suggests the use of topical anaesthesia for routine cataract surgery.

Administration, Topical↗
PubMed2005

Choice of intraocular lens may not affect refractive stability following cataract surgery.

PURPOSE: To assess whether the choice of an intraocular lens (IOL) with rigid haptics (Sensar) or an IOL with pliable haptics (Acrysof) has an effect on refractive stability following cataract surgery. METHODS: Seventy-three patients were recruited consecutively as they returned for their 6-month visit following cataract surgery. There were 37 patients who had received an Acrysof IOL and 36 who had received a Sensar IOL. Each patient had their refractive error measured at the 1-month postoperative visit. At the 6-month follow-up visit, refraction was repeated. The change in refractive error was then compared between IOL groups and other factors that may affect postoperative refractive stability including preoperative refraction, axial length, keratometry, wound type and wound meridian. RESULTS: An Acrysof IOL showed minimal myopic movement, whereas a Sensar IOL was more likely to move hypermetropically. However, this difference was not statistically significant (t=1.92; P=0.06). The magnitude of the shift in spherical equivalent in either direction for the Acrysof group was 0.37 +/- 0.35 D and for the Sensar group was 0.28 +/- 0.31 D. Again, this difference was not statistically significant (t=1.17; P=0.25). However, preoperative anterior chamber depth was associated with postoperative refractive shift (t=2.66; P=0.009). Furthermore, patients with a scleral wound showed a small against-the-rule shift in cylindrical refractive error. No other factors were associated with postoperative refractive shift amongst the sample. CONCLUSIONS: There were no clinically significant differences in postoperative refractive stability between the Acrysof and Sensar groups. However, preoperative anterior chamber depth was associated with the magnitude of shift in spherical equivalent.

Acrylic Resins↗
PubMed2006

Refractive and visual outcome of paediatric cataract surgery in the Ukraine.

PURPOSE: To describe the refractive and visual outcomes after surgery for congenital or developmental cataract in the Ukraine. METHODS: Cataract surgery was performed in 65 children aged 3-15 years. The cataracts were bilateral in 44 children and unilateral in 21. Examinations, including visual acuity (VA) and objective refraction using retinoscopy, were performed preoperatively and at 1 day, 6 months and 2 years postoperatively. Neither occlusion therapy nor spectacles were prescribed. RESULTS: Almost all children (96%) gained in VA. In all, 40% of the bilateral cases achieved a corrected Snellen VA > or = 0.5 and 44% of the unilateral cases obtained a corrected VA > or = 0.2. The difference between VA (logMAR) preoperatively and 2 years postoperatively was statistically significant (p < 0.05). The bilateral cases showed a postoperative reduction in mean astigmatism from 3.9 D (1 day postoperatively) to 0.6 D (2 years postoperatively) (p < 0.001), while the unilateral cases showed a reduction from 4.2 D (1 day postoperatively) to 0.4 D (2 years postoperatively) (p < 0.001). CONCLUSION: Good postoperative VA was achieved in the group with bilateral cataract. Surprisingly, even in the group with unilateral cataract, an increase in VA was obtained, despite the lack of postoperative correction with glasses or occlusion therapy.

Adolescent↗
PubMed1999

Randomised clinical trial of lensectomy versus lens aspiration and primary capsulotomy for children with bilateral cataract in south India.

AIMS: The primary objective was to determine which surgical technique gave the best long term visual outcome for infants and young children with bilateral symmetrical cataract in south India. Secondary objectives were to assess complications and the need for further surgical intervention. METHODS: A randomised controlled clinical trial was undertaken. 65 children under 10 years old with bilateral cataract had one eye treated by lensectomy and the other by aspiration with primary capsulotomy. RESULTS: 56 children (86%) with a mean age at surgery of 53 months were reviewed 3 years after surgery. The overall binocular acuity was 6/18 or better in 57.1% and 6/60 or better in 94.6%. There was no difference in visual acuity between the matched pairs of eyes undergoing aspiration or lensectomy at the third year of follow up (p=0.57). Aspiration eyes were more likely to require a secondary procedure to restore vision than lensectomy eyes (66.1% v 1.8%). CONCLUSION: Aspiration with primary capsulotomy gives an acceptable visual outcome in this part of India providing that there is good follow up to manage capsule opacification. If secondary intervention is not possible owing to poor compliance with follow up, then lensectomy is likely to give better long term visual rehabilitation providing there is good maintenance and technical support for the lensectomy equipment.

Amblyopia↗
PubMed1998

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 (CeeOntrade mark& ;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.

Aged↗
PubMedDate not supplied

Development of posterior capsule opacification in the rabbit.

PURPOSE: The aim of the present study was to characterize the development of after-cataract in the rabbit by measuring its wet weight, protein, DNA and glycosaminoglycan (GAG) contents and using Scheimpflug and slitlamp analysis. Further, aqueous humor (AqH) leukocytes, protein and lens epithelial cell proliferation activity were determined. METHODS: AqH was collected and capsular bags including after-cataract were dissected free on days 0, 1, 7, 14, 28 and 56 after cataract surgery. The wet weights were determined and the contents of DNA, protein and GAG in the capsular bags including after-cataract were analyzed. AqH was analyzed for leukocytes, protein and proliferative activity. In another set of experiments, rabbit eyes were analyzed by the Scheimpflug technique and slitlamp examination on days 0, 1, 7, 14, 28 and 56 after cataract surgery. The wet weight of the capsular bag with the after-cataract was also determined. RESULTS: An increase was found in the wet weight (480%) and the contents of protein (221%), DNA (945%) and GAG (336%) of the capsular bags including after-cataract during the experimental period. In the AqH, all 3 variables measured, leukocytes, protein and proliferative activity, reached their highest levels on day 1 after surgery. In the second set of experiments, the wet weight of the capsular bag including after-cataract increased by 391% during the 56-day experimental period. Posterior capsule opacification (PCO), as measured by Scheimpflug analysis, increased from 0.8 to 81.7% and the scores of Elschnig's pearls as well as fibrosis, analyzed by slitlamp, increased from 0.0 to 2.8 and 3.0, respectively. CONCLUSIONS: This study shows that the same components that are reported to be important in human PCO are also components of PCO in the rabbit. Thus, the rabbit model seems to accurately reflect human PCO development, and because PCO develops much faster in rabbits that would make the rabbit model suitable for studies to elucidate human PCO development.

Animals↗
PubMed1999

Animal study on the effects of catalin on aftercataract and posterior capsule opacification.

PURPOSE: To find out the role of Catalin in the prevention of posterior capsular opacification (PCO), we undertook this experimental study in rabbits. METHODS: Twenty rabbits (10 for the Catalin group and 10 for the placebo group) were operated on for extracapsular clear lens extraction in an aseptic environment. In all cases, capsulorrhexis of 8 mm diameter was carried out. Both the test drug and placebo were given at a dose of 4 times/day from the first postoperative day for 8 weeks. Common drugs in both groups were topical corticosteroid, antibiotic and cycloplegic drops. Periodic slitlamp examinations and photographic documentations were carried out to find any evidence of aftercataract. At the end ot 8 weeks, histopathological examination was carried out to document any evidence of aftercataract. RESULT: Overall, evidence of aftercataract was seen in 6 rabbits in the control group and 3 in the Catalin group; the degree of PCO was higher in the placebo group. CONCLUSION: We found that Catalin played some role in preventing PCO.

Animals↗
PubMedDate not supplied

Phacoemulsification and intraocular lens implantation for angle closure glaucoma after the relief of pupillary block.

PURPOSE: We studied the surgical outcomes of phacoemulsification and intraocular lens (IOL) implantation for cataract and/or uncontrolled intraocular pressure (IOP) in eyes with angle closure glaucoma. SETTING: Department of Ophthalmology, National Nagasaki Medical Center, Nagasaki, Japan. METHODS: Eighteen eyes from 15 patients after laser iridotomy (17 eyes) or peripheral iridectomy (1 eye) had undergone surgery and were studied. We used an iris retractor in 7 eyes due to insufficient mydriasis and a capsular tension ring in 2 eyes due to phacodonesis during the operation. The patients were followed up for at least 6 months (13.8 +/- 7.2 months; range: 6-36 months). RESULTS: The mean IOP significantly decreased from 17.4 +/- 8.1 to 13.5 +/- 3.3 mm Hg at 6 months after surgery. The IOP was below 21 mm Hg in all eyes. The visual acuity was not worsened in any eyes and became better than 2 Snellen lines in 14 eyes. The corneal endothelial cell count decreased from 2,365 +/- 517 to 1,960 +/- 661/mm2 (18.3 +/- 17.2%). CONCLUSIONS: Phacoemulsification and IOL implantation is useful in IOP control for angle closure glaucoma after relief of pupillary block. However, we should take care of operative complications because of a shallow anterior chamber, poor mydriasis and zonular weakness.

Aged↗
PubMedDate not supplied

Lens epithelial cell migration between posterior capsule and intraocular lens with variously finished posterior optic edge and two haptic angulations.

PURPOSE: To compare lens epithelial cell migration between intraocular lens (IOL) optics and the posterior capsule of IOLs with various edges and haptic angulations. METHODS: Experimental acrylic IOLs with 3 types of finishing (none, polishing, tumbling and polishing) and 2 types of haptic angulation (10 and 15 degrees ) as well as 3 (AcrySof MA30BA, Sensar AR40, CeeOn 911) clinically implanted IOLs were inserted in rabbit eyes. Scanning electron-microscopic examination of IOLs was carried out before surgery and histological examination of lens capsules 3 weeks after surgery. The grading of lens epithelial cell migration under the IOL was made by scoring. RESULTS: Scanning electron-microscopic examination showed that the optic edge sharpness decreased according to the finishing in experimental IOLs. The AcrySof and CeeOn lenses had sharp edges and the Sensar had a rounded edge. The migration score was highest in the IOL with a rounded edge whereas it was lowest in IOLs with a sharp edge and large haptic angulation. There was no significant difference between the scores of clinically implanted IOLs. CONCLUSION: Sharpness of the optic edge may be a critical factor for the prevention of posterior capsule opacification and more important than haptic angulation in acrylic IOLs.

Acrylic Resins↗
PubMed2003

In vitro study on the closure of posterior capsulorrhexis in the human eye.

PURPOSE: An unexplained clinical observation is the development of posterior capsular opacification (PCO), even when the central part of the posterior capsule has been removed. The purpose of this study was to investigate in vitro the mechanisms involved in the closure of the posterior capsulorrhexis in a capsular bag model. METHODS: A sham extracapsular cataract extraction was performed in 71 human donor eyes, followed by a central posterior capsulorrhexis 3 to 4 mm in diameter. Each capsular bag was pinned to a PMMA ring with a central hole of 5 mm and placed in a Petri dish. The capsular bags were cultured and monitored for 3 to 7 weeks by phase-contrast microscopy, after which they were prepared for light, transmission, and scanning electron microscopy. RESULTS: Proliferation of lens epithelial cells (LECs) within the posterior rhexis area was found in 22 cases (31%) of which 3 had a complete closure. In the absence of the posterior capsule, a monolayer of LECs was observed growing on a basal lamina, consisting of loosely arranged fibers. Further observations on noncultured capsular bags revealed that this basal lamina corresponds to the anterior hyaloid membrane. CONCLUSIONS: This study corroborates the clinical observation that LECs that remain after cataract extraction have the potential to proliferate, in the absence of their natural substrate, on a basal lamina of vitreous origin and are able to close the posterior capsulorrhexis partially or totally in approximately one third of cases.

Adolescent↗
PubMed2003

A new model of posterior capsule opacification in rodents.

PURPOSE: To describe a new model of posterior capsule opacification (PCO) in rodents METHODS: An extracapsular lens extraction (ECLE), by continuous curvilinear capsulorrhexis and hydrodissection, was performed in 42 consecutive Brown Norway rats. Animals were killed at 0, 6, and 24 hours and 3, 7, and 14 days after surgery. Eyes were enucleated and processed for light microscopy and immunohistochemistry. RESULTS: In 34 (81%) of the animals the operated eye appeared well healed before death, with a clear cornea and a well-formed anterior chamber. In eight (19%) there was no view of anterior segment structures because of hyphema, fibrin, or corneal opacification. PCO was clinically evident 3 days after ECLE and was present in all animals at 2 weeks. Immediately after ECLE, lens epithelial cells (LECs) were present in the inner surface of the anterior capsule and lens bow. Twenty-four hours after surgery, LECs started to migrate toward the center of the posterior capsule. At 3 days, multilayered LECs, some spindle shaped, were present throughout the lens capsule. Capsular wrinkling was apparent. Lens fibers and Soemmering's ring were observed in all animals 14 days after surgery, indicating some degree of cellular differentiation. Activated macrophages were present in greater numbers at 3 and 14 days after surgery (P < 0.05), when proliferation and migration of LECs appeared to be greatest, and lens fiber differentiation was evident, respectively. CONCLUSIONS: In rodents PCO occurs after ECLE and is associated with low-grade inflammation, mostly of mononuclear macrophages. Although no intraocular lens implantation was performed, this model appears to be valuable for studying the sequence of events that leads to PCO after cataract surgery and the extracellular matrix cues that promote lens fiber differentiation.

Animals↗
PubMedDate not supplied

Posterior capsule opacification and wrinkling in a case of capsular bag distension.

We describe a complication following anterior neodymium: YAG laser capsulotomy in a case of capsular bag distension which was diagnosed 21 months after cataract extraction with phacoemulsification and in-the-bag lens implantation. An anterior neodymium: YAG capsulotomy was performed and immediately after this the posterior capsule collapsed and wrinkled, causing a marked decrease in visual acuity that necessitated posterior neodymium: YAG capsulotomy.

Anterior Chamber↗