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Changing concept and modern techniques in cataract surgery.

Until the middle of the 80-ies the routine method of cataract surgery was intracapsular extraction (ICCE). Approximately 10 years ago the so called extracapsular cataract extraction (ECCE) started to become more and more widely used. After extracapsular cataract extraction had come into general use, it became possible to implant the IOL behind the iris, into the left in place capsular bag of the original lens. We usually perform extracapsular cataract extraction with posterior chamber lens (PCL) implantation as a routine procedure. In the last few years phacoemulsification started to gain acceptance. During this operation one breaks the nucleus of the lens into pieces with the help of ultrasound, and this way it is possible to remove both the nucleus and the cortex of the lens through a small wound. The first step in learning phacoemulsification is to be able to create a perfectly round hole on the anterior capsule (capsulorhexis). Besides using various manual techniques we introduced diathermal capsulotomy for capsulorhexis. This latter procedure is becoming more and more popular as it is safe, easy to perform, and gives excellent result.

Capsulorhexis↗

A retrospective comparison of techniques to prevent secondary cataract formation following posterior chamber intraocular lens implantation in infants and children.

PURPOSE: To determine the effect of various methods of managing the posterior capsule and anterior vitreous on the rate of posterior capsular opacification in children implanted with posterior chamber intraocular lenses (PC IOL). METHODS: We reviewed the charts of 20 eyes of 15 children (1.5-12 years) who underwent primary cataract surgery with PC IOL in the last 5 years. The posterior capsule and anterior vitreous were managed in a variety of ways: in 5 eyes the posterior capsule was left intact, and 15 eyes underwent posterior continuous curvilinear capsulorhexis (PCCC)-nine cases without and 6 with anterior vitrectomy. In 8 eyes posterior optic capture was performed, 3 with and 5 without vitrectomy. The follow-up ranged from 1 to 4.5 years (mean: 2 years). RESULTS: Visually significant secondary cataract developed in all 5 eyes with intact posterior capsules and in the 4 eyes that underwent PCCC without vitrectomy and without posterior optic capture (i.e., the optic was left in the capsular bag). The optical axis remained clear in all 6 eyes that underwent PC IOL implantation with vitrectomy (with or without posterior optic capture). Initially, all optic capture cases without vitrectomy also remained clear, but after 6 months 4 out of 5 developed opacification. CONCLUSIONS: In this series posterior capsulorhexis with anterior vitrectomy was the only effective method of preventing or delaying secondary cataract formation in infants and children.

Capsulorhexis↗

Controlling the capsular shape in lens refilling.

OBJECTIVES: To investigate control of the capsular shape by determining the ability of the lens capsule to mold injected silicone and to evaluate the relationship among the volume of silicone injected, refraction, and the amplitude of accommodation. METHODS: After endocapsular phacoemulsification following an upper, minicircular capsulorhexis, the lens capsule of a pig eye was refilled with a silicone mixture that polymerizes in vitro in 2 hours. The minicircular capsulorhexis opening was sealed by a small silicone plug to prevent leakage. The anterior capsule curvature and refraction of the lens were measured by a Scheimpflug camera and lensometer, respectively, with and without zonular tension. Zonular tension was created using a ciliary ring sutured to the ciliary bodies and expanded. RESULTS: The mean (+/- SD) anterior curvature of the lenses without zonular tension was 6.50 +/- 0.07 mm after 17 hours and 6.54 +/- 0.04 mm after 42 hours; with zonular tension it was 7.01 +/- 0.11 mm and 7.23 +/- 0.24 mm, respectively. The curvature became flatter when zonular tension was applied or steeper when zonular tension was abolished momentarily during measurements after 17 hours, but after 42 hours the curvature was unaffected by the application or removal of zonular pressure. The mean (+/- SD) amplitude of accommodation (the difference between refraction without zonular tension and that with it) was 3.2 +/- 0.5 diopters (D), 6.1 +/- 1.8 D, 4.8 +/- 0.8 D, and 2.8 +/- 1.3 D, when the lens was refilled with a silicone volume corresponding to 45%, 55%, 75%, and 95%, respectively, of the mean normal lens volume. CONCLUSIONS: The lens capsule possesses some ability to mold the injected silicone during its polymerization. When the eye is atropinized, the lens capsule may conform to its nonaccommodated state. Accommodation could be obtained by various degrees of refilling. Moderate refilling yields a greater amplitude of accommodation than does more complete refilling. Using a silicone plug to seal the capsular opening facilitates lens refilling with excellent reproducibility and seems to be useful in research.

Accommodation, Ocular↗

Separation of fibres from the capsule enhances mitotic activity of human lens epithelium.

Proliferation and migration of lens epithelial cells is at the origin of after-cataract, currently the main side effect of cataract surgery. Extracapsular cataract surgery necessitates opening of the anterior lens capsule and removal of the lens fibres before an intraocular lens can be placed in the cleaned capsular bag. The present study was aimed at testing the potential of the lens capsule and the fibres to affect the mitotic activity of the lens epithelial cells in human donor eyes. Pairs of human lenses used in this study were subjected to two different experimental conditions. In the first, only a small anterior capsulorhexis was made. In the other, fibres were separated from the epithelium by gentle hydrodissection, the nucleus was rotated and, either left in the capsular bag or removed by hydroexpression. The specimens were cultured for 48 hr in MEM with 2% serum. Mitotic activity was assessed by immunohistochemistry using the bromodeoxyuridine (BrdU) incorporation technique. Fellow lenses of the same donors were cultured intact as controls. Anterior capsulorhexis showed a small but significant (P < 0.02) increase in the number of BrdU positive nuclei in the equatorial region but not in the wound area. Lenses where fibres were separated from the epithelium showed a large increase in BrdU incorporation in the germinative region, as compared to the intact control lenses (P < 0.01). BrdU incorporation was highest when fibres were removed. Lens capsule integrity and the presence of contacts between fibres and epithelial cells may have a role in the control of the mitotic activity of the lens epithelium. The data recorded here could be useful for understanding lens cell biology and prevention of after-cataract.

Adolescent↗

[Quantitative evaluation of acrylic and silicone intraocular lenses with a sharp optic edge design].

BACKGROUND: At the Department of Ophthalmology, Heidelberg, Germany, posterior capsule opacification (PCO) of a silicone and an acrylic intraocular lens (IOL) with a sharp optic edge design was evaluated. PATIENTS AND METHODS: In a prospective study either the AMO ClariFlex silicone IOL or the Sensar AR40e hydrophobic acrylic IOL were implanted in 47 patients following uneventful phacoemulsification. Mean patient age was 76.2+/-7.8 (ClariFlex) and 73.4+/-12.9 years (AR40e), respectively. The mean follow-up time was 19.7+/-5.34 in the ClariFlex and 21.9+/-1.89 months in the AR40e group. PCO development was evaluated postoperatively using the EPCO 2000 analysis software (scale 0-4). Areas of interest were the total IOL optic, the central 3-mm zone as well as the capsulorhexis. RESULTS: In both groups, all patients achieved a BCVA of 20/32 (AR40e) and 20/25 (ClariFlex), respectively. There was a very low incidence of PCO development with a mean EPCO score of 0.07+/-0.2 (ClariFlex and 0.15+/-0.2 (AR40e). Within the 3-mm zone and the capsulorhexis, there was a tendency for even lower EPCO scores in both groups. We calculated a statistically significant difference for the two lens materials for all investigated IOL areas (Wilcoxon's test, p<0.05). CONCLUSION: Both IOLs with a sharp edge design showed good functional results, a stable position in the capsular bag as well as a low incidence of PCO development. However, the silicone IOL showed statistically significantly lower PCO scores.

Acrylic Resins↗

[Scanning electron microscopy studies of human lenses].

BACKGROUND: In order to better understand the mechanism of tearing of the human lens capsule during circular capsulorhexis, scanning electron microscopic (SEM) examinations were made particularly of the rhexis edge. MATERIALS AND METHODS: Anterior segments from cornea donor eyes, as well as capsular pieces extracted during cataract surgery, were studied after fixation in glutaraldehyde, critical point drying, and sputtering with gold. RESULTS: The edges of the capsulorhexis were found to be very regular even in the area of zonular attachment. Neither the surface of the lens capsule nor the edge of the rhexis itself indicated any morphological influence on the direction of tearing. CONCLUSION: From the results we conclude that the rhexis of the lens capsule is only directed by the forces applied and not by particular morphological structures. To avoid radial tears, a deep anterior chamber, resulting in a relief of the anterior zonular portion seems most important. This minimizes radial forces on the anterior lens capsule, which provides the best condition for a safe rhexis.

Cataract Extraction↗

Single-piece AcrySof in the newborn rabbit eye.

PURPOSE: To evaluate the behavior of the single-piece AcrySof SA30AT intraocular lens (IOL) (Alcon) in the eyes of newborn rabbits and to compare the postoperative complications in aphakic and pseudophakic eyes. SETTING: St. Erik's Eye Hospital, Stockholm, Sweden. METHODS: Clear lens extraction was performed in both eyes of 20 3-week-old rabbits. In 1 randomly selected eye in each rabbit, a single-piece acrylic IOL was implanted. Preoperatively and 1 and 2 months postoperatively, axial length and corneal diameter were measured. Corneal thickness was measured at the endpoint. The rabbits were also examined clinically; the position of the IOL and signs of secondary glaucoma were noted. At 2 months, the 19 surviving animals were killed. In 10 rabbits, the wet mass of the after-cataract was measured, and the eyes of 9 rabbits were fixed in formalin for histologic evaluation. RESULTS: One animal died soon after surgery. Three rabbits developed secondary glaucoma in the aphakic eye. No rabbit developed glaucoma in the pseudophakic eye. In the 16 animals without secondary glaucoma, there were no significant differences in corneal diameter at 1 and 2 months or in corneal thickness at the endpoint; the axial length was significantly longer in aphakic eyes at 1 month, but not at 2 months. The aphakic eyes developed more posterior synechias and the pupil size at 1 and 2 months was significantly smaller in aphakic eyes than in pseudophakic eyes. Significantly more after-cataract developed in aphakic eyes than pseudophakic eyes (eyes with secondary glaucoma included). No difference in inflammation was seen between eyes in the histologic evaluation. In 11 of 19 pseudophakic eyes, the anterior capsulorhexis was not completely on the optic. In these eyes, the optic moved partly forward into the anterior chamber. CONCLUSION: The single-piece AcrySof SA30AT IOL seems to induce less inflammation and probably inhibits secondary glaucoma. It does not retard eye growth as much as previously tested IOLs. However, it is important to keep the entire capsulorhexis margin on the optic, especially in these small eyes.

Animals↗

Biocompatibility of poloxamer hydrogel as an injectable intraocular lens: a pilot study.

PURPOSE: To induce irreversible gelation of poloxamer, a thermosensitive polymer hydrogel, by using a photoinitiator and ultraviolet (UV) irradiation and to verify the biocompatibility and use of poloxamer as an injectable intraocular lens (IOL) material. SETTING: Department of Ophthalmology, Seoul National University College of Medicine, Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. METHODS: In 10 rabbits, endocapsular phacoemulsification was performed and a poloxamer-photoinitiator mixture was injected into the capsular bag through a small capsulorhexis site. In 1 eye, the capsulorhexis site was closed with a small plug and the entire eye was irradiated with UV light for 5 minutes. Postoperatively, poloxamer transparency and effect on the conjunctiva, cornea, iris, vitreous, and retina were observed. RESULTS: A mixture comprising 25% poloxamer and 0.01% photoinitiator produced a poloxamer that remained transparent in the lens capsule for up to 6 months. No inflammatory response or toxicity was observed in the conjunctiva, cornea, iris, vitreous, or retina. CONCLUSION: Poloxamer is a potentially suitable material for an injectable IOL. Further study is needed.

Animals↗

Capsular bag shrinkage after implantation of a capsular bending or capsular tension ring.

PURPOSE: To evaluate the influence of a capsular bending ring (CBR) or tension ring (CTR) on capsular bag shrinkage. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, and Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz, Germany. METHODS: In 92 eyes of 92 patients, a capsular measuring ring (CMR) was implanted after phacoemulsification to measure capsular bag size in vivo. Patients were randomized into 3 groups: The first received a CMR and CBR, the second received a CMR and CTR, and the third received a CMR alone. Measurements were performed preoperatively, intraoperatively, during the first 3 postoperative days, and after 1 and 3 months. Preoperative biometric characteristics such as axial length (AL) and anterior chamber depth were determined. Primary clinical end points were capsular bag size and capsulorhexis diameter measured intraoperatively and by means of slitlamp biomicroscopy and retroillumination photography postoperatively. RESULTS: There were no clinically relevant group differences in AL, anterior chamber depth, or capsulorhexis diameter. Eyes implanted with the CBR showed shrinkage of the capsular bag from 10.6 to 10.4 mm after a median of 3 months (sign test; P = .023); eyes with a CTR showed comparable median capsular bag shrinkage from 10.5 to 10.2 mm (P<.001), whereas eyes without a CTR showed a median shrinkage from 10.5 to 10.0 mm (P<.001). Intraindividual shrinkage was of a similar, although significantly different, order among these groups (median shrinkage 0.15 versus 0.23 and 0.38 mm, respectively; all pairwise Wilcoxon test; P = .050, P = .020, P<.001, respectively). CONCLUSIONS: Capsular shrinkage can be inhibited by a CBR and, to lesser extent, a CTR; the gain in shrinkage prevention is limited when compared with a CMR, however. This conclusion can be drawn only for the specific CBR or CTR and hydrophobic acrylic intraocular lens (IOL) used in this study. Reduction of capsular bag shrinkage after CTR implantation may reduce IOL dislocation and tilt and help to maintain postoperative visual acuity.

Adult↗

Phacoemulsification with topical anesthesia: Resident experience.

PURPOSE: To compare the intraoperative and postoperative complications and outcomes of phacoemulsification performed by residents using topical and retrobulbar anesthesia. SETTING: Two university ophthalmology departments. METHODS: One hundred fifty phacoemulsification procedures were performed by 3 residents who used retrobulbar anesthesia (retrobulbar group), and 146 phacoemulsification procedures were performed by another 3 residents who used topical anesthesia and who had no experience with retrobulbar or peribulbar anesthesia (topical group). Case notes were prospectively compared. The data analyzed included the ocular history, intraoperative and postoperative complications, and final best spectacle-corrected visual acuity (BSCVA). RESULTS: There were no differences between the 2 groups in complication rates. Anterior capsule tears occurred in 8 eyes (5.3%) in the retrobulbar group and 7 eyes (4.7%) in topical group. Capsulorhexis was continuous but not curvilinear in 14 eyes (9.3%) and 12 eyes (8.2%), respectively. Capsulorhexis tear or posterior capsule rupture that necessitated conversion to extracapsular cataract extraction occurred in 3 eyes (2.0%) in the retrobulbar group and in 1 eye (0.6%) in the topical group. Posterior capsule rupture with vitreous loss occurred in 10 eyes (6.6%) and 9 eyes (6.1%), respectively. Loss of lens fragments in the vitreous cavity occurred in 3 eyes (2.0%) and 4 eyes (2.7%), respectively. The 63 postoperative complications (41 eyes [27.3%], retrobulbar group; 22 eyes [15.0%], topical group) included cystoid macular edema, intraocular lens decentration, endophthalmitis, bullous keratopathy, transient intraocular pressure elevation, temporary corneal edema, and vitreous hemorrhage. Some cases had more than 1 complication. The BSCVA, including in eyes with preexisting ocular pathology, was 20/40 or better in 86.7% in the retrobulbar group and 84.9% in the topical group. CONCLUSION: When supervised and in selected patients, residents who have no retrobulbar or peribulbar anesthesia experience can safely perform phacoemulsification using topical anesthesia.

Adult↗

Effect of a closed foldable equator ring on capsular bag shrinkage in cataract surgery.

PURPOSE: To evaluate the effect of a closed foldable equator ring (CFER) versus a conventional capsular tension ring (CTR) on capsular bag shrinkage. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: In this prospective study, 70 eyes of 70 patients were randomized to 2 groups using a 1:1 block scheme. After uneventful cataract surgery, a capsular measuring ring was implanted in all eyes to measure the capsular bag diameter in vivo. In Group 1, a CTR was implanted in the capsular bag. In Group 2, a CFER was inserted. Biometric characteristics such as axial length and the horizontal and vertical corneal radii were measured preoperatively. The capsular bag diameter and capsulorhexis diameter were measured intraoperatively and 2 or 3 days as well as 1 and 3 months postoperatively. RESULTS: There were no statistically significant or clinically relevant between-group differences in covariants such as axial length, vertical and horizontal corneal radii, and capsulorhexis diameter. Eyes with the CTR had slight but statistically significant capsular bag shrinkage from a median of 10.4 to a median of 10.2 mm after 3 months (P<.001). Eyes with the CFER also had slight but statistically significant capsular bag shrinkage from a median of 10.3 to a median of 10.2 mm 3 months postoperatively (P = .021). At baseline, the CTR group had a larger capsular bag diameter, but there were no statistically significant differences between the groups at the 3-month follow-up (P = .669). CONCLUSIONS: No clinically relevant capsular bag shrinkage was observed after implantation of a CFER or a CTR. The expected capsular bag shrinkage was the same in both groups.

Aged↗

Hyperopic shift in refraction associated with implantation of the single-piece Collamer intraocular lens.

PURPOSE: To describe reports of refractive hyperopic shift over time following intraocular lens (IOL) implantation, discuss possible etiologies, and suggest preventive and therapeutic treatments. SETTING: Multiple U.S. ophthalmic surgical centers; data collection at Staar Surgical, Monrovia, California, USA. METHODS: Forty cases displaying a progressive hyperopic shift in refraction after implantation of the single-piece Collamer IOL (Staar Surgical) were reported to the manufacturer out of 160 000 that have been implanted since its commercial introduction in April 2000. A retrospective data analysis of these 40 cases was performed; parameters included the mean refractive change over time, presence of capsular fibrosis, IOL displacement, and outcomes of secondary treatments. Individual case examples are presented. RESULTS: The mean refractive shift was 1.81 diopters (D) (range 0.25 to 3.75 D) with 5 cases (14%) demonstrating a hyperopic shift greater than 3.0 D. In 38 of the 40 cases, some combination of the following were reported: posterior displacement of the IOL, capsule fibrosis, and/or relief of the condition by performance of a radial or circumferential anterior neodymium:YAG capsulotomy to relieve capsule tension. The use of a small (less than 5.5 mm) capsulorhexis was also associated with cases showing the hyperopic shift. CONCLUSION: The most likely etiology was the development of anterior capsule fibrosis, sometimes exacerbated by a small capsulorhexis, which could cause the IOL to move posteriorly, resulting in a hyperopic change in refraction. Previous in vitro testing by the manufacturer ruled out a change in the refractive power of the IOL in the eye as a cause of this phenomenon.

Aged↗

Epithelial transdifferentiation and cataract in the human lens.

Anterior subcapsular cataracts cause a serious loss of vision and are normally associated with ocular trauma, inflammation or clinical skin conditions. They appear to be accompanied by epithelial cell growth and transdifferentiation where unscheduled production of a number of proteins, including alpha smooth muscle actin (alpha-sma), occurs. Clinical studies have also revealed an up-regulation of the TGFbeta signalling pathway in such cataracts. The present study, using phase contrast and immunofluorescent techniques, was undertaken to investigate the extent of alpha-sma expression in traumatic cataracts, in capsulorhexis specimens obtained during cataract surgery and in aged human lenses from donor eyes. The donor lenses were also exposed to trauma or TGFbeta in culture to observe their relative contribution to alpha-sma production. Dense anterior subcapsular cataracts were relatively rare (<1%), but all showed a pronounced up-regulation of alpha-sma, which was located both in anterior cells of normal appearance and in nucleated fibroblastic cells lying beneath the anterior epithelium. Surprisingly, more than 50% of capsulorhexis specimens from mature cataracts showed expression of alpha-sma, although to a limited extent. Alpha-sma was not expressed in any of the clear donor lenses and culture for 8 days in EMEM did not induce expression. Interestingly, unlike their young animal counterparts, human lenses failed to show the presence of alpha-sma when exposed to 10 ng ml(-1) TGFbeta. However, after culture, lenses with pre-existing cortical opacities did express alpha-sma, as did clear lenses subjected to injury or trauma. It appears that the greater the stress, the greater is the expression of alpha-sma. Cataract, and especially cortical cataract, should therefore be seen as associated with stress-induced signalling pathways in the lens that lead to the transdifferentiation of the anterior epithelial cells.

Actins↗

Decentration and tilt of polymethyl methacrylate, silicone, and acrylic soft intraocular lenses.

PURPOSE: The purpose of the study is to investigate the periodic changes regarding the decentration and tilt of the intraocular lens (IOL) and to compare any differences in the decentration and tilt among polymethyl methacrylate (PMMA), silicone, and acrylic soft IOLs. METHODS: A total of 225 cataractous eyes undergoing IOL implant surgery were randomized into 3 groups based on the type of IOL: group A, one-piece PMMA IOL; group B, three-piece silicone IOL; and group C, three-piece acrylic soft IOL. Both the length of the decentration and the degree of the tilt of the IOL were quantitated using the Anterior Eye Segment Analysis System (EAS-1000). All eyes underwent EAS-1000 examinations at 1 week as well as 1, 3, 6, 9, and 12 months after surgery. RESULTS: All IOLs were confirmed to be implanted accurately in the capsular bag after continuous curvilinear capsulorhexis was accomplished. No statistically significant differences were observed regarding the IOL decentration or tilt between the various postoperative periods in any of the three IOL groups. Furthermore, the differences regarding both the IOL decentration and the tilt between the three IOLs were not determined to be statistically significant throughout the observation period. CONCLUSIONS: As long as the IOL was placed properly in the capsular bag after the continuous capsulorhexis, neither the decentration nor the tilt of the IOL showed a significant progression up to 12 months after surgery. Furthermore, both the extent of the decentration and tilt almost were the same among the PMMA, silicone, and acrylic soft IOLs.

Acrylic Resins↗

The capsular tension ring: designs, applications, and techniques.

Originally, the open poly(methyl methacrylate) (PMMA) capsular tension ring (CTR) was designed to compensate for zonular defects or to stretch the posterior capsule in highly myopic eyes not receiving an intraocular lens (IOL). We address the variety of subsequent designs, applications, and techniques that have evolved. With pre-existing or intraoperative zonular defects, a standard CTR may be inserted before or at any time during cataract removal to maintain or re-establish an extended capsular diaphragm. For profound zonular dialysis or weakness, a CTR was designed for scleral fixation. Capsular tension rings with integrated tinted sector shields have been developed to compensate for sector iris colobomas or aniridia. The CTR has also been used as a measuring gauge for in vivo quantification of capsule dimensions and postoperative capsular shrinkage. The CTR has improved control during primary posterior capsulorhexis and prevented oval distortion along the lens axis postoperatively. During combined cataract and vitreous surgery, a CTR prevents capsule damage and provides undisturbed peripheral visualization before IOL implantation. Capsular tension rings may also influence capsule opacification formation. A special band-shaped CTR with sharp edges was developed to inhibit lens epithelial cell migration and avoid capsulorhexis-optic contact.

Anterior Chamber↗

Capsule contraction syndrome.

Capsule contraction syndrome is an exaggerated reduction in anterior capsulectomy and capsular bag diameter after extracapsular cataract surgery. While rarely seen with can-opener-style capsulectomies with anterior radial capsular tears, it is relatively frequent with capsulorhexis. It is particularly common in patients with pseudoexfoliation and in eyes with a history of moderately severe uveitis. Its effects, which include extreme reduction in the capsulectomy opening, malposition of the opening, reduction in equatorial capsular diameter, and displacement of the IOL, seem more exaggerated in small capsulorhexis openings and in the older patient. Neodymium: YAG laser radial anterior relaxing capsulotomies done within three weeks of cataract surgery reduce the sphincter effect of the contraction and lessen the chronic zonular-traction-related complications of the condition, which may include spontaneous IOL dislocation and retinal detachment.

Aged↗

Polishing methods for the lens capsule: histology and scanning electron microscopy.

Capsule opacification occurs when lens epithelial cells remains on the capsule after extracapsular cataract surgery. The cells divide and form fibers. The best way to prevent opacification is to remove all epithelial cells from the capsule. Our study compared the efficacy of different mechanical polishing methods in eyes in which cataracts were removed by endocapsular phacoemulsification through a miniature capsulorhexis. The capsular bag was polished using one of five techniques: metallic scrapers, silicone scrapers, Rentsch capsule curettes, irrigation/aspiration tip, or ultrasound irrigation/aspiration tip. Then a circular central portion of the anterior capsule was removed and processed for histology and scanning electron microscopy. A control group comprised unpolished central anterior capsules obtained by capsulorhexis before or after endophacoemulsification. The cleanest capsules were obtained by polishing with the ultrasound irrigation/aspiration tip.

Aged↗

Evaluation of a one-piece poly(methyl methacrylate) intraocular lens with a 7 mm biconvex optic and a total diameter of 10 mm.

To find out how large the total diameter of an open-loop intraocular lens (IOL) should be, we studied 90 consecutive implantations of a one-piece poly(methyl methacrylate) IOL with a 7 mm biconvex optic and a total diameter of 10 mm (Adatomed 75 ST). The lens design made implantation simple, even through a small capsulorhexis. In 85% of the cases, the IOL remained well centered. One case with asymmetric placement of the IOL showed a decentration of more than 1 mm. In 14% of the eyes slight decentrations occurred because the capsular bag was too large. Contact between the iris and IOL was found in 15%. In 4% there were folds in the posterior capsule, and in 35% there was a small space between the IOL and the posterior capsule because the capsular bag was too large. Although the ST lens has a small total diameter, it remained at a distance from the iris in most cases. In-the-bag implantation through a continuous central capsulorhexis is mandatory to avoid secondary displacement; nevertheless, slight decentrations cannot be excluded. For a large capsular bag, the total diameter of an IOL should exceed 10 mm. Clinical results, cellular reaction on the lens surface (26.6%), biocompatibility, and visual performance are comparable to those of other well-approved poly(methyl methacrylate) IOLs.

Adult↗