Evaluation of 50 silicone posterior chamber lens implantations

Solving intraocular lens-related pigment dispersion syndrome with repositioning of primary sulcus implanted single-piece IOL in the capsular bag

We describe 2 cases of pigment dispersion syndrome (PDS) after uneventful phacoemulsification and implantation of a posterior chamber single-piece intraocular lens (IOL) with a sharp-edge design. In both cases, several days after IOL implantation, marked pigment dispersion was seen on the iris and in the trabecular meshwork, associated with an elevation in intraocular pressure (IOP). Thorough examination showed that the implanted IOL was in the ciliary sulcus. After surgical repositioning of both IOLs in the capsular bag, the pigment dispersion regressed and the IOP returned to normal limits. The 2 cases suggest that particularly in PDS patients, an IOL with an anterior sharp-edge design should be implanted in the capsular bag. Implantation in the ciliary sulcus should be avoided.

Secondary pigmentary glaucoma associated with piggyback intraocular lens implantation

A 51 year-old man developed bilateral pigmentary glaucoma with uncontrolled intraocular pressure (IOP) and signs of pigmentary dispersion syndrome after piggyback intraocular lens (IOL) implantation. Cataract surgery had been performed with in-the-bag implantation of poly(methyl methacrylate) IOLs in both eyes. Increasing myopia was subsequently corrected with implantation of an AcrySofIOL (Alcon Laboratories) in the ciliary sulcus of each eye. After the second implantation, the IOP was unresponsive to antiglaucoma medications, the visual field was damaged, and the visual acuity decreased. Ultrasound biomicroscopy showed that the haptics and the sharp edge of the IOL were chafing the posterior surface of the iris. After the IOL in the sulcus was removed, the IOP was stabilized by medications. This case highlights the importance of the IOL choice for sulcus implantation to avoid the complications of pigmentary dispersion syndrome.

Plate-haptic silicone intraocular lens implantation: long-term results

PURPOSE

To present the 10- to 12-year functional and morphological results of in-the-bag implantation of a foldable, plate-haptic, silicone posterior chamber intraocular lens (IOL).

SETTING

Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria.

METHODS

Between September 1987 and December 1989, 160 silicone posterior chamber IOLs (Staar AA-4203C) were implanted in the capsular bag through a 3.5 mm corneoscleral incision after a continuous curvilinear capsulorhexis was created. In spring 1999, 36 patients (38 eyes) could be included in a follow-up examination.

RESULTS

The median follow-up was 10.5 years +/- 2 (SD). The mean visual acuity was 0.82 +/- 0.34. The mean refraction (spherical equivalent) was +0.57 diopter (D), an insignificant change from the mean at the first postoperative follow-up at 1 month (+0.40 D). Slitlamp examination showed mildly dispersed pigment on the IOL surface in 81.58% of cases. All IOLs had a Tyndall effect (clouding). In 84.21%, the effect was minimal, in 10.53% it was moderate, and in 5.26% it was more intense. Ninety-two percent of the IOLs were centered within 0.5 mm. Of the 22 cases of decentration (57.89%), 86.36% were toward the 12 o'clock position in the bag. The neodymium:YAG capsulotomy rate was 10.52%. There were no cases of IOL-related inflammation or a clinically significant cystoid macular edema.

CONCLUSION

The 10- to 12-year results suggest favorable clinical results of implantation of Staar AA-4203C plate-haptic, silicone posterior chamber IOLs.

[History of the development of intraocular lenses]

Even though cataract surgery has been practiced for over 2000 years, modern cataract surgery started just some 50 years ago. with the first IOL implantation by Sir Harold Ridley. The development of intraocular lenses was accompanied by great successes and disasters. With the fast development of cataract surgical techniques over the past 15 years (ECCE, Phacoemulsification, Capsulorhexis) a successful marriage between IOL-developments and surgery was established. Indication profiles for cataract surgery and IOL implantation extended to more and more patient groups. At this time classical cataract surgery is further developing into refractive intraocular lens surgery to correct higher ametropia in clear lens or phakic eyes. This development was only possible because of the improvements of surgical techniques and implants in classical cataract surgery.

Pigment dispersion with elevated intraocular pressure after AcrySof intraocular lens implantation in the ciliary sulcus

A 45-year-old white woman had phacoemulsification with intraocular lens (IOL) implantation. The surgery was routine except for a linear tear in the posterior capsule; there was no disruption of the anterior vitreous face. After residual soft lens matter was removed, an AcrySof IOL was placed in the ciliary sulcus. One month postoperatively, the patient presented with an intraocular pressure (IOP) of 30 mm Hg and signs of pigment dispersion with 360 degrees of heavy pigmentation of the trabecular meshwork and iris transillumination defects. Intraocular pressure was controlled with a topical beta-blocker. The optic disc appearance and visual field remained normal, but the uniocular hyperpigmentation of the trabecular meshwork was still present. We hypothesize that the sharp square edge of the AcrySof IOL increases the risk of a chafing effect on the posterior iris pigment and advocate that this IOL be placed in the capsular bag and ideally have 360 degrees of protective overlapping of the anterior capsule over the edge of the optic.

Dislocation of a plate-haptic silicone intraocular lens into the anterior chamber

Posterior dislocation is a well-described complication of plate-haptic intraocular lenses (IOLs). It usually occurs after an opening in the posterior capsule, either intraoperatively or after a neodymium: YAG capsulotomy occurs. We report a case of anterior luxation of a plate-haptic silicone IOL occurring 4 months after uneventful cataract surgery. This case emphasizes the need for a small and continuous capsulorhexis as well as in-the-bag implantation of plate-haptic IOLs.

Occurrence of pigment precipitates after small incision cataract surgery

PURPOSE

To assess the incidence of pigment precipitates and potential association with glaucoma, diabetes, and/or intraocular lens (IOL) optic center thickness in patients having small incision cataract surgery and foldable IOL implantation.

SETTING

Eye Care Physicians of Michigan, Jackson, Michigan, USA.

METHODS

A retrospective data analysis was conducted of patients with a preoperative diagnosis of glaucoma or diabetes or in whom pigment precipitates had been reported after cataract surgery. Group 1 consisted of 23 patients in whom pigment precipitates had been reported and Group 2, 92 patients in whom no precipitates were reported. Two statistical models were used to analyze preoperative, demographic, surgical, and postoperative variables and determine potential correlations. An overall incidence of the occurrence of pigment precipitates was calculated based on the total number of patients with foldable IOLs.

RESULTS

The incidence of pigment precipitates was 0.35% (n = 23/6519). Mean time to occurrence was 5.5 months. No between-group differences were found in pathologies or other demographics or postoperative variables. Intraocular lens size and implantation correlated with the occurrence of pigment precipitates.

CONCLUSION

The development of pigment precipitates after foldable IOL implantation did not appear to be affected by the presence of glaucoma or diabetes. Newer, slimmer IOL styles and refined insertion techniques were associated with a lower occurrence of precipitates.

Capsular capture of silicone intraocular lenses

PURPOSE

To examine the incidence of capsular capture in silicone IOL implantation and determine its effect on visual acuity.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

METHODS

This study comprised 144 eyes that had phacoemulsification with three-piece silicone intraocular lens (IOL) implantation that were evaluated about 3 months after surgery. The examination included the status of the haptic and optic placement, extent of posterior capsular opacification (PCO), and the best corrected visual acuity.

RESULTS

One hundred twenty-eight eyes had an in-in haptic placement, 15 had in-out placement, and 1 had out-out placement. Capsular capture occurred in 30 eyes (20.8%). The extent of PCO in eyes with capsular capture was greater than in those without capture. The best corrected visual acuity in eyes with capsular capture was worse than in those without capture. In addition, eyes with in-out and out-out haptic placement had significantly worse PCO and visual impairment than the eyes with in-in placement.

CONCLUSION

There was a high incidence of capsular capture after silicone IOL implantation. This complication, along with the undesirable placement of the haptics, led to PCO and thus visual impairment.

Reduced vision secondary to pigmented cellular membranes on silicone intraocular lenses

PURPOSE

Visually significant, pigmented cellular membranes may form on intraocular lenses after implantation. We studied a series of patients to determine the onset, visual significance, treatment, and recurrent nature of these pigmented membranes in patients who underwent surgery with silicone lens implantation.

METHODS

In nine eyes (eight patients) with visually significant pigmented cellular membranes on their Allergan Medical Optics (Irvine, California) silicone intraocular lenses (model SI18NGB or SI26NB), eight underwent combined phacoemulsification, intraocular lens implantation, and trabeculectomy; one underwent phacoemulsification and lens implantation only. We reviewed medical records to identify preoperative, operative, and postoperative similarities and differences in care. Clinical examinations and slit-lamp photographs, over an average of 21.3 +/- 7.2 months (range, 11 to 31 months), documented the effects of different treatment modalities.

RESULTS

The patients sought treatment ten to 20 weeks (mean, 15 weeks) postoperatively. Except for the cellular membranes, each eye was without evidence of inflammation or cystoid macular edema. Subjective complaints decreased, and best-corrected Snellen visual acuity improved with topical corticosteroid therapy alone. Pretreatment best-corrected visual acuities ranged from 20/40 to 20/400 (mean, 20/70 using Snellen fractions) and improved two to eight (mean, five) Snellen lines, to a range of 20/20 to 20/50 (mean, 20/25). All nine eyes had recurrence of the membranes after treatment terminated and required a maintenance regimen of corticosteroid eyedrops.

CONCLUSION

The pigmented cellular membranes observed on these silicone lenses were visually significant to each patient. The membranes resolved and visual acuity improved with topical corticosteroid treatment alone but recurred in all patients on cessation of treatment.

Long-term clinical results of AMO PhacoFlex model SI-18 intraocular lens implantation

The AMO PhacoFlex Model SI-18 was the first commercially available three-piece silicone intraocular lens (IOL) for use in small incision cataract surgery. Allergan Medical Optics' silicone IOLs have been implanted in more than 750,000 patients worldwide over the past eight years. This report of the FDA clinical investigation of the AMO PhacoFlex model SI-18 IOL summarizes one year follow-up data from the initial premarket approval clinical trial on 500 core patients implanted with the SI-18 lens. One-year follow-up data from 5,860 patients in the modified core group and three-year follow-up data on the 500 patient core/modified core group are also presented. At three years postoperatively, 91.3% of best case core/modified core patients achieved 20/40 or better corrected visual acuity. Overall incidence of persistent complications at three years was 3.2%.

Assessment of the blood-aqueous barrier by fluorophotometry following poly(methyl methacrylate), silicone, and hydrogel lens implantation in rabbit eyes

Intraocular lenses of silicone, hydrogel, or acrylic materials that can be implanted through small incisions are being proposed as an alternative to conventional poly(methyl methacrylate) lenses. The potential of each of these materials to stimulate intraocular inflammation is important in their selection as an implantable material. To investigate the potential of each material, we assessed by clinical slitlamp examination, fluorophotometry, and histopathology the inflammatory response induced in the rabbit eye following phacoemulsification and implantation of hydrogel, silicone, or poly(methyl methacrylate) intraocular lenses. All lenses seemed to be equally well tolerated. In general, the degree of inflammation seen clinically decreased over the four-month study; however, anterior segment fluorophotometry showed continued mild interruption of the blood-aqueous barrier in all lens groups. Fluorophotometry is a sensitive method to assess persistent subclinical anterior segment inflammation.

Intraocular pressure following small-incision cataract surgery and polyHEMA posterior chamber lens implantation. A comparison between acetylcholine and carbachol

Ninety patients who had phacoemulsification and implantation of a flexible polyHEMA intraocular lens (IOGEL 1103) were assigned to three groups. After evacuation of sodium hyaluronate retrolentally from the capsular bag, 0.5 ml of 1% acetylcholine chloride, 0.01% carbachol, or balanced salt solution was instilled into the anterior chamber following wound closure. Intraocular pressure (IOP) was measured the day before, and six hours, 18 hours, and one week postoperatively. No topical or systemic antiglaucomatous drug was given during the study period. Preoperatively and one week postoperatively there was no significant difference between the three groups (P greater than .01). At six hours postoperatively the mean IOP decreased in the carbachol group (-2.8 mm Hg) and increased in the acetylcholine and control groups (+0.6 mm Hg and +/- 4.7 mm Hg) when compared with baseline pressures. At 18 hours the mean change from baseline was -3.0 mm Hg in the carbachol group, +0.8 mm Hg in the acetylcholine group, and +2.3 mm Hg in the control group. At six hours IOP exceeding 22 mm Hg was observed in ten of the control patients (30%) receiving balanced salt solution intracamerally and four of the acetylcholine patients (13.3%) but none of the carbachol patients. At 18 hours IOP remained above 22 mm Hg in three of the acetylcholine patients (10%) and four of the control patients (13.3%). Only one of the carbachol patients developed an increase of IOP up to 26 mm Hg at 18 hours. Removal of viscoelastic substances from behind the IOL reduced the incidence of pressure spikes in the early postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Posterior capsule opacification

A complication of extracapsular cataract extraction with or without posterior chamber intraocular lens (PC-IOL) implantation is posterior capsule opacification. This condition is usually secondary to a proliferation and migration of residual lens epithelial cells. Opacification may be reduced by atraumatic surgery and thorough cortical clean-up. Clinical, pathological and experimental studies have shown that use of hydrodissection, the continuous curvilinear capsulorhexis and specific IOL designs may help reduce the incidence of this complication. Capsular-fixated, one-piece all-polymethylmethacrylate PC-IOLs with a C-shaped loop configuration and a posterior convexity of the optic are effective. Polymethylmethacrylate loops that retain "memory" create a symmetric, radial stretch on the posterior capsule after in-the-bag placement, leading to a more complete contact between the posterior surface of the IOL optic and the taut capsule. This may help form a barrier against central migration of epithelial cells into the visual axis. Various pharmacological and immunological methods are being investigated but conclusive data on these modalities are not yet available.

Combined small-incision cataract surgery and trabeculectomy--technique and results

In a prospective study 35 eyes of 25 patients with coexisting cataract and glaucoma underwent trabeculectomy, phacoemulsification and implantation of a folded polyHema intraocular lens through the trabeculectomy opening. Follow-up ranged from 6 to 27 months (mean 13.3). The mean age was 76.4 (68 to 88 years). 22 eyes suffered from primary open angle glaucoma, 10 eyes from a pseudoexfoliation glaucoma and 3 eyes had a chronic angle closure glaucoma. Preoperatively intraocular pressure was controlled in 10 eyes with a mean medication of 2.1 but uncontrolled in 25 eyes (mean medication: 2.5). The preoperative visual acuity ranged from 20/40 to hand motions. Postoperatively intraocular pressure was controlled (< 18 mmHg) in all (100%) eyes and without therapy in 32 (91%) eyes. Three (9%) eyes had to be treated with topical timolol twice a day after surgery. Mean intraocular pressure dropped from 21.2 +/- 6.0 mmHg preoperatively to 13.5 +/- 2.1 mmHg postoperatively. Vision improved in all but 4 eyes, 25 (74%) achieving a visual acuity of 20/40 or better. The causes for failed improvement or deterioration of vision were senile macular degeneration in 2 eyes and central retinal vein occlusion and vascular optic nerve atrophy in one eye respectively. Post-operative complications included hyphema in 9 (26%) eyes, fibrin effusion to a various extent into the anterior chamber in 19 (54%) eyes and delayed hypotony (< 5 mmHg) with chorioidal effusion in 1 (3%) eye. Fibrin effusion was frequently observed in eyes with intraocular pressure below 10 mmHg, iris surgery and hyphema. Finally the complications did not effect the results regarding visual acuity or glaucoma control.(ABSTRACT TRUNCATED AT 250 WORDS)

Keratometric cylinder and visual performance following phacoemulsification and implantation with silicone small-incision or poly(methyl methacrylate) intraocular lenses

Silicone and poly(methyl methacrylate) (PMMA) intraocular lenses from Allergan Medical Optics were implanted in the posterior chamber of 96 cataract patients with small or standard incisions following phacoemulsification. Significantly less keratometric cylinder (astigmatism) and better uncorrected visual acuity were observed during the six week postsurgical follow-up in the patients who received the small incision silicone lens than in those who received the standard PMMA lens.

Evaluation of 150 consecutive cases of poly HEMA posterior chamber lenses implanted in the bag using a small-incision technique

We report the results of 150 capsular bag implantations of the IOGEL PC-12 hydrogel lens. Mean follow-up was seven months. Following capsulorhexis and phacoemulsification, a Faulkner folder was used to insert the lens through a 3.5 mm to 4.0 mm scleral tunnel incision. Initially, a number of surgical complications were encountered. Because of increasing experience and modified instrumentation and technique, these did not occur in the later cases. Visual results were good, all eyes gaining a best case visual acuity of 20/40 or better and 97% achieving 20/25 or better. Morphological results were satisfactory. Generally the lenses remained centered and at a distance from the iris. Retention of viscoelastic substance or debris between the lens and the posterior capsule, occasionally observed at the start of the series, has been avoided by retrolental aspiration. Persistent pigment dispersion, which was observed when the lens had been implanted in the sulcus, was not seen. Tolerance of the lens material was generally satisfactory. There were six cases (4%) of fibrinoid uveitis, which is a relatively high incidence. From our experience and results we conclude that this implantation procedure allowed controlled insertion and placement of the IOGEL lens, provided that adequate instrumentation and technique was used; visual performance was comparable to that of poly(methyl methacrylate) lenses; capsular bag fixation furnished satisfactory morphological results, provided an adequately shaped capsulorhexis was performed.

Forces on intraocular lens haptics induced by capsular fibrosis. An experimental study

Electronic dynamometry measurements, performed upon intraocular lens (IOL) haptics of prototype one-piece three-loop silicone lenses, accurately defined the relationships between elastic force and haptic displacement. Lens implantations in the capsular bag of dogs (loop span equal to capsular bag diameter, loops underformed immediately after the operation) were evaluated macrophotographically 5-8 months postoperatively. The highly constant elastic property of silicon rubber permitted quantitative correlation of subsequent in vivo haptic displacement with the resultant force vectors responsible for tissue contraction. The lens optics were well centered in 17 (85%) and slightly offcenter in 3 (15%) of 20 implanted eyes. Of the 60 supporting loops, 28 could be visualized sufficiently well to permit reliable haptic measurement. Of these 28, 20 (71%) were clearly displaced, ranging from 0.45 mm away from to 1.4 mm towards the lens' optic center. These extremes represented resultant vector forces of 0.20 and 1.23 mN respectively. Quantitative vector analysis permits better understanding of IOL-capsular interactions.

Comparison of contrast sensitivity between posterior chamber lenses of silicone and PMMA material

Seventeen patients received a posterior chamber lens of PMMA in one eye and a silicone lens (Staar Surgical Co.) in the other. Contrast sensitivity was examined in both eyes in order to detect differences with respect to the material used for lens implantation. An attempt was made to exclude any changes in the eyes that were not due to lens implantation and that might possibly have an influence on the result. A paired T-test was performed for each spatial frequency. No statistically significant difference was found between the two materials with regard to contrast sensitivity.

Tissue reaction after silicone and poly(methyl methacrylate) intraocular lens implantation: a light and electron microscopy study in a rabbit model

We describe the histopathologic results of extracapsular lens extraction and silicone and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation in 36 rabbit eyes. Phase-contrast microscopy was used to examine precipitates on IOL surfaces and posterior capsules. Semithin and ultrathin sections were taken from the central cornea, anterior uvea, capsular bag, and retina near the posterior pole. The follow-up was one to 16 weeks. Silicone IOLs did not cause significantly less precipitation than PMMA IOLs. Precipitates consisted of spindle-shaped fibroblast-like cells, various forms of inflammatory cells and multinucleated giant cells, single melanophages, and irregularly arranged birefringent collagen fibers. Corneal endothelial edema was slightly more prominent in PMMA IOL implanted eyes. Significant retinal edema in the posterior pole area was not observed with either of the two lens types. Severe precipitation in the form of large clusters of pigment cells and inflammatory reactions seemed to depend on mechanical trauma (iris capture and lens dislocation) and individual animal reactions, but not on the lens type used.

Evaluation of the first 60 cases of poly HEMA posterior chamber lenses implanted in the sulcus

Flexible lenses allow folding and inserting through a small incision. Using Faulkner's forceps, 60 hydrogel lenses were implanted in the sulcus through a 3.5 mm pocket incision following phacoemulsification. Mean follow-up was six months. The lens was suitable for the procedure when it was properly handled. When it was not, untimely unfolding or tears occurred, necessitating prolonged maneuvering in the eye or sometimes replacement of the lens which caused increased trauma. Though functional results were comparable to those achieved with polymethylmethacrylate lenses, all eyes achieving a visual acuity of 20/40 or better, morphological results were less satisfactory. Because of hydrogel's lack of adhesiveness and the inability to estimate the individual sulcus diameter, pseudophakodonesis was a common observation. The lens touching the posterior iris surface caused pigment dispersion (37%), sometimes leading to secondary pigment glaucoma. For this reason, we now favor capsular bag fixation.

Advantages and limitations of current soft intraocular lenses

We report our clinical experience with six soft intraocular lenses: (1) STAAR silicone, (2) CooperVision/Schlegel silicone, (3) IOLAB silicone, (4) Allergan Medical Optics (AMO) silicone, (5) Fyodorov silicone, and (6) Alcon hydrogel (IOGEL). We found that these soft intraocular lenses have several common design problems. The single-size design of five of the six soft lenses can lead to a windshield-wiper decentration effect in lenses too small for larger eyes. We observed several instances in which the one-piece lenses became decentered, subluxed, and vaulted anteriorly against the iris or posteriorly away from the iris as postoperative capsulozonular changes occurred. We found that the insertion methods for these soft lenses need refining to reduce the risk of intraocular damage and wound stretching if the lenses are to be folded and inserted through a small 3.0 mm to 3.5 mm incision. The surface and physical characteristics of these lenses may also require further study. We observed folding grooves, sebacium deposits, and rust from the insertion instrument on some lenses inside the postoperative eye and pigment dispersion associated with hydrogel lenses. We conclude that small diameter polymethylmethacrylate implants are the best choice for small incision cataract surgery at this time.