Foldable Silicone Intraocular Lens Research Articles

Long-term follow-up of three-piece, looped, silicone intraocular lenses

Purpose: To present long-term follow-up of silicone lens implantation.Setting: Clinique Ophtalmologique, Centre Saint-Victor, Amiens, Cédex, France.Methods: In this prospective study, we followed 111 eyes consecutively operated on from March 1988 to July 1989. Foldable silicone intraocular lenses (IOLs) were implanted in 107 eyes and poly(methyl methacrylate) (PMMA) IOLs in 4 eyes. The eyes with PMMA lenses were excluded from the study.Results: After a follow-up of 3 years (average 20 months), 13.7% of eyes with posterior capsule opacification (PCO) required a neodymium:YAG (Nd:YAG) laser capsulotomy. In the group with longer follow-up (average 57 months), 40.6% required Nd:YAG capsulotomy. The majority of capsulotomies were performed in the fourth year after surgery. The PCO rate was the same whether the IOL was placed in the sulcus or in the capsular bag (51.5 versus 48.5%). The Nd:YAG treatment caused pitting of the silicone in most cases, with no effect on visual acuity. We did not observe other serious complications such as retinal detachment, endophthalmitis, or silicone discoloration. There was no visual acuity below 20/35.Conclusions: In this series, the silicone IOLs were compatible with phacoemulsification and did not have a higher rate of complications than has been reported for PMMA IOLs.

Long-term endothelial cell loss following phacoemulsification through a temporal clear corneal incision

Purpose: To evaluate central endothelial cell loss (ECL) following clear corneal cataract surgery using two different incision sizes and the effect of ultrasound time (UST) and power on postoperative ECL and various cell parameters.Methods: Fifty-eight patients had phacoemulsification through temporal, two-step clear corneal tunnel incisions. In Group A (n = 28), a one-piece, plate-haptic, foldable silicone intraocular lens (IOL) was implanted through a 3.5 mm sutureless incision. In Group B (n = 30), a poly(methyl methacrylate) IOL was implanted through a 5.0 mm incision with one radial suture. The central endothelial cell counts were recorded preoperatively and postoperatively at 2 to 5 days, after 6 months, and after 1 year. Color-coded, computer-assisted specular microscopy was used for special cell analysis after 1 year.Results: Collective data showed an ECL of 7.9 ± 4.1 % (mean ± standard deviation) at 2 to 5 days postoperatively, 6.7 ± 2.9% after 6 months, and 7.3 ± 3.3% after 1 year. A direct linear relationship was found between ECL and UST and power: ECL increased as UST and power increased. After 1 year, ECL in Group A was 4.2% with UST ≤1 1/2 minutes, 6.7% with UST ≥ 1 1/2 to 2 1/2 min, and 9.6% with UST > 2 1/2 to 3 1/2 min; in Group B, it was 6.0%, 7.5%, and 11.4%, respectively. Specular microscopy showed normal, age-related cell parameters 1 year postoperatively.Conclusions: Phacoemulsification with 3.5 mm clear corneal incisions produced slightly less ECL (6.7%) than phacoemulsification with 5.0 mm incisions (7.9%). Total ECL of 7.3% at 1 year postoperatively compared favorably with ECL rates of other cataract extraction methods.

Prospective study of the SI-40NB foldable silicone intraocular lens

Purpose: To evaluate the surgical performance and postoperative outcomes of 100 consecutive implantations of the new AMO PhacoFlex SI-40NB foldable intraocular lens (IOL).Setting: Concord Hospital and Dalcross Private Hospital, Sydney, Australia.Methods: This prospective study comprised 100 consecutive patients who had endocapsular phacoemulsification cataract surgery with implantation of the AMO SI-40NB IOL, which has a silicone optic and poly(methyl methacrylate) (PMMA) haptics. Patients were excluded if trabeculectomy was performed concomitantly. The main outcome measures were control of folding, ease of implantation, centration, intraoperative and postoperative complications, and visual acuity. A minimum of 4 months follow-up was planned.Results: Mean follow-up was 4.3 months ± 2.1 (SD) (range 1 to 12 months). The lens permitted excellent control of folding and insertion, as well as excellent centration at surgery and 4 months. There was one lens-related intraoperative complication because of crimping of the trailing lens haptic. Postoperative complications were minimal, and 92% of patients achieved a visual acuity of 20/20 or better at 1 and 4 months. Excluding the eyes with retinal pathology, 100% achieved 20/20 or better at 4 months.Conclusion: The AMO SI-40NB three-piece silicone IOL with PMMA haptics provided excellent operative control, centration, and visual outcome and is suitable for small incision cataract surgery.

Oberflächenqualität faltbarer Intraokularlinsen aus Silikon - Eine rasterelektronenmikroskopische Studie

Soft intraocular lenses (IOLs) have been developed to be folded during insertion to allow implantation through a small incision. The surface of the IOL is of great importance in postoperative inflammation and long-term acceptance of the implant. Rough and sharp edges can damage delicate intraocular tissues. The purpose of this study was to analyze new, foldable silicone IOLs for surface quality prior to and following folding. Eleven silicone IOLs of different types were included in this study (four one-piece plate-haptic silicone IOLs and seven three-piece silicone IOLs with polypropylene, PMMA or polyimid haptics). We performed scanning electron microscopy on brand-new IOLs prior to and following folding either with forceps or inserter. Special attention was given to the silicone optic surface, optic edges, haptic-optic junctions and the haptic itself. Photographs were taken at 5-350 times magnification. All IOLS demonstrated a smooth and homogeneous optic surface at low magnification. At high-power magnification (X 350), distinctive surface patterns were evident in some IOLs, which turned out to be artefacts. The edge finish showed surplus silicone material and molding flash in six of 11 IOLs. Positioning holes of the 4 plate-haptic IOLs were, except in one IOL, rounded and not rough. Photographs of the haptic-optic junctions revealed surplus material or clefts between the haptic and optic in six of the 7 three-piece IOLs; the loop ends of two IOLs showed a roughened or irregular surface. We did not detect any IOL changes produced by folding. The silicone IOLs tested demonstrated generally acceptable surface properties, but most IOLs had regional surface irregularities of varying magnitude. The clinical impact of these remains to be established, but surplus material or surface defects might result in deposition of inflammatory cells, protein or microorganisms and synechia formation. Folding of the IOLs did not produce superficial defects.

Condensation on the Posterior Surface of Silicone Intraocular Lenses during Fluid—Air Exchange

Posterior chamber foldable silicone intraocular lenses (IOLs) are becoming increasingly prevalent in patients undergoing a pars plana vitrectomy with fluid-air exchange. The authors report an important limitation of foldable silicone IOLs during fluid-air exchanges in pars plana vitrectomies. The charts of 18 pseudophakic patients with foldable silicone IOLs who underwent vitrectomy with fluid-air exchange by the authors were reviewed. There was a statistically significant difference in the occurrence of condensation during fluid-air exchange between the group of patients with a capsulotomy versus those that did not have a capsulotomy (P = 0.003). Condensation limiting the view of the retina occurred during fluid-air exchange in 11 of 11 of the patients with foldable silicone lenses and a capsulotomy. Attempts to remove the condensation with a soft-tipped aspiration cannula resulted in limited view of the retina for 1 to 2 minutes in 6 of 11 patients. Use of a thin film of silicone oil restored the view in one patient. In the presence of an intact posterior capsule, condensation did not occur on identical foldable silicone IOLs in seven of seven patients. Recognition of the presence of a foldable silicone lens is important when an air-fluid exchange is anticipated. If a capsulotomy is present, the surgeon must be aware that condensation may limit the view of the retina severely during and after surgery. Intraoperatively, the view of the retina usually can be restored in short surgeries by wiping the posterior lens surface with a soft-tipped cannula, and in more complex surgeries by applying a thin film of silicone oil on the posterior surface of the lens.

Long-term results of implantation of a plate haptic silicone lens in the capsular sac

An important step in developing cataract surgery was the introduction of soft foldable silicone intraocular lenses in the middle 80's. Functional and morphological long-term data are a vital base for definite conclusions on the new material's safety and biocompatibility. Our study presents the long-term results after the implantation of a silicone posterior chamber lens with solid plate haptic design (STAAR AA-4203). All lenses were folded and implanted through a 4-mm small corneoscleral incision. Our study includes 54 eyes in 52 patients with a mean follow-up period of 56.5 +/- 8.9 months. A visual acuity of 20/40 or better was found in 90.7% of all eyes. All except one of the 33 eyes without any further preexisting ocular pathology at the time of the operation achieved a visual acuity of 20/40 or better. Two thirds of all eyes had a horizontal astigmatism of +1.0 D or less. By slitlamp examination more or less dispersed pigment was seen on the IOL's surface in 46.3%. 83% of the silicone lenses were centrated within 0.5 mm. A YAG-laser capsulotomy was performed in 7 cases (13%). IOL-related intraocular inflammations, cystoid macular edema or an elevated intraocular pressure did not occur in this group. Our satisfactory long-term results suggest an excellent biocompatibility of the IOL's design and material.

Combined trabeculectomy, cataract extraction, and foldable lens implantation

The efficacy of foldable silicone intraocular lenses in combined glaucoma/cataract surgery was retrospectively analyzed in 19 consecutive operations. Preoperatively all patients were receiving medical treatment for glaucoma; 21% had intraocular pressures above 21 mm Hg despite the medical therapy. Postoperatively, reduction of intraocular pressure to 21 mm Hg or less was achieved in 84% of eyes, with 58% requiring no antiglaucoma medications. Mean improvement of Suellen visual acuity was 4.9 lines; 84% of eyes achieved a final acuity of 20/40 or better. Median follow-up was 59 weeks (range 25 to 88 weeks). Thirteen eyes (68%) had a filtration bleb present when last examined. These preliminary results suggest that foldable silicone IOLs are an effective alternative to poly(methyl methacrylate) lenses in combined glaucoma/cataract surgery.

Scanning electron microscopic study of modern silicone intraocular lenses

Silicone, as manufactured today, appears to be a biocompatible material. The safety and efficacy of silicone lenses are primarily related to the intraocular lens (IOL) design. We compared the edge finish of two three-piece polypropylene loop foldable silicone IOL designs (Allergan Medical Optics) and three one-piece designs (Staar Surgical Co., CooperVision-Cilco). Except for an early Staar one-piece design, all lenses including the more recent Staar lenses had acceptably smooth edges with minimal molding flash.