Anterior chamber lenses. Part II: A laboratory study

An analysis of 606 surgically removed anterior chamber intraocular lens (IOL) specimens revealed that 351 or 58% of these were small-diameter, round loop, closed-loop styles. Because of the extremely high percentage of IOLs with this design received in our laboratory and the correlation of clinical histories with our histopathologic findings, we have concluded that such IOLs do not provide the safety and efficacy achieved by other anterior chamber lens designs. The finely polished, one-piece, all-PMMA styles fared well in our study. Although these one-piece styles comprise well over 50% of the American market share of anterior chamber IOLs, they comprise only 14% of all anterior chamber IOLs accessioned in our laboratory, compared to 58% for closed-loop designs. We believe that implantation of anterior chamber lenses with small-diameter, round, closed loops is no longer warranted. Patients in whom these IOLs have already been implanted should be carefully followed. It is our opinion that the FDA should recall or closely monitor all IOLs of this design and that implantation of closed-loop lenses should be discontinued in the United States. Furthermore, we believe that an IOL deemed to be not medically sound or worthy of implantation in the United States should not be marketed or donated outside of this country.     

Intraocular lens explantation and exchange. A review of lens styles, clinical indications, clinical results, and visual outcome.

We conducted a retrospective review of 102 patients who had intraocular lens (IOL) explantation or exchange over a 7.5 year period. Seventy-one patients had IOL exchange while 31 had lens removal without exchange. Anterior chamber IOLs comprised 66.7% of the lenses removed. The most frequent indication for anterior chamber IOL explantation was pseudophakic bullous keratopathy (PBK), followed by the uveitis-glaucoma-hyphema syndrome and cystoid macular edema. Of the IOLs removed, 17.6% were iris-supported, with PBK being the most common indication for removal. Posterior chamber IOLs comprised 15.7% of the explanted lenses in this series. Lens dislocation/decentration was the leading indication for IOL removal in the posterior chamber IOL group. Among the 71 patients who had IOL exchange, 71.8% received an anterior chamber lens and 28.2% received a posterior chamber lens. Visual outcome following IOL exchange or removal showed that 40 patients (39%) improved, 47 patients (46%) had the same vision, and 15 patients (15%) had worse vision postoperatively. The most common reason for a worsening of vision postoperatively was corneal decompensation, followed by glaucoma and cystoid macular edema. Analysis of the clinical results revealed that 86.3% of the patients who had an exchange with an anterior chamber IOL had a successful outcome with either improvement or stabilization of the ocular condition. Ninety percent of the patients who received a posterior chamber IOL had a successful clinical outcome.     

Penetrating keratoplasty for pseudophakic bullous keratopathy. Management of the intraocular lens

Management of the intraocular lens (IOL) at the time of penetrating keratoplasty (PK) for pseudophakic bullous keratopathy has been based on lens-related factors and coexisting anterior segment abnormalities. The authors reviewed the results of PK for 102 cases of pseudophakic bullous keratopathy (43 anterior chamber, 50 iris-supported, and 9 posterior chamber) with respect to: (1) the type of IOL, (2) coexisting abnormalities, and (3) management of the IOL at surgery. Graft failure after 2 years of follow-up was: (1) retained iris-supported IOLs, 9%; (2) retained anterior chamber IOLs, 60%; (3) retained posterior chamber intraocular lenses (PC IOL), 0%; (4) removed IOLs, 9%; and (5) exchanged IOLs, 20%. After 5 years of follow-up, 13 of 13 PKs with retained closed-loop anterior chamber IOLs had failed. Visual results were best in eyes with retained iris-supported, rigid anterior chamber or PC IOLs and when the IOL was removed without replacement. The authors recommend that closed-loop anterior chamber lenses and unstable lenses of any type be removed or exchanged and that well-fixated PC IOLs and iris-clip IOLs be retained at the time of PK for pseudophakic bullous keratopathy.     

Indications for and results of intraocular lens explantation.

We reviewed the medical records of 97 patients who had 101 consecutive intraocular lens (IOL) explantation procedures, with or without exchange, at the University of Florida Eye Center from January 1, 1983, to December 31, 1987. The majority of the removed IOLs were anterior chamber styles (53.9%), followed by iris-fixated lenses (33.7%). The most common indications for surgery included pseudophakic bullous keratopathy (PBK)--69%, uveitis-glaucoma-hyphema (UGH) syndrome--9%, and IOL instability--7%. The best visual outcome was seen in patients with IOL instability; 50% achieved 20/40 or better visual acuity. Forty one percent of patients with PBK, who had IOL explantation/exchange combined with penetrating keratoplasty, achieved 20/40 or better visual acuity. The poorest visual outcome was seen in patients with the UGH syndrome; 83% had a final acuity of 20/200 or worse. However, these patients achieved resolution of their pain and inflammation and better control of their intraocular pressure as a result of the surgery. Complications leading to IOL explantation tended to occur months to years after the original surgery in patients with closed-loop, semi-flexible anterior chamber lenses and iris-fixated lenses. Posterior chamber lenses were most often removed because of complications unrelated to the implant.     

Position of angle-supported, iris-fixated, and ciliary sulcus-implanted myopic phakic intraocular lenses evaluated by Scheimpflug photography

PURPOSE: To examine postoperative positional stability of myopic phakic intraocular lenses (IOLs). DESIGN: Prospective, nonrandomized clinical study. METHODS: The study included 46 eyes which received an anterior chamber angle-supported (Bausch & Lomb NuVita; 10 eyes), anterior chamber iris-fixated (Ophtec Artisan; 20 eyes) or ciliary sulcus-implanted phakic IOL (Staar ICL; 16 eyes). The distance between the phakic IOL and the crystalline lens and the cornea as well as rotation around the optical axis was evaluated using Scheimpflug photography at 1, 3 to 6, and 12 months postsurgery. RESULTS: The anterior chamber phakic IOLs showed no significant movement in anteroposterior direction. The posterior chamber phakic IOL showed a significant movement toward the crystalline lens between postoperative months 3 and 12. The median amount of rotation around the optical axis between the 3- and the 12-month evaluation was 1.9 degrees (range = 0.0-33.5 degrees) for the NuVita, 0.6 degrees (range = 0.0-3.5 degrees) for the Artisan, and 0.9 degrees (range = 0.2-2.3 degrees) for the ICL. Four NuVita IOLs rotated more than 10 degrees. CONCLUSIONS: The angle-supported anterior chamber phakic IOLs showed a generally stable position regarding distance to cornea and natural lens, but rotation was observed in four IOLs. The iris-fixated phakic IOL showed the highest overall stability. The posterior chamber phakic IOL was stable in terms of rotation but had a tendency to decrease in distance toward the crystalline lens. Intraocular lenses implanted in phakic eyes followed for 12 months demonstrate stable IOL position overall.     

Posterior capsular opacification and intraocular lens decentration. Part I: Comparison of various posterior chamber lens designs implanted in the rabbit model

Experimental phacoemulsification procedures were performed in 54 Rex rabbits. In 96 eyes, posterior chamber intraocular lenses (IOLs) were implanted in the capsular sac, and 12 eyes served as controls with no lens implantation. The IOLs were divided into eight groups consisting of both one-piece and three-piece styles with various optic designs. Each lens was evaluated for the relative effect on posterior capsular opacification (PCO) and optic decentration, two of the most common complications of modern cataract surgery and IOL implantation. Optics with a convex-anterior, plano-posterior design (the type of IOL optic most frequently implanted today) had the highest incidence of PCO. With capsular fixated IOLs, the features that have a statistically significant impact on reducing PCO include (1) one-piece, all-polymethylmethacrylate (PMMA) IOL styles, (2) a biconvex or posterior convex optic design, and (3) angulated loops. Lens decentration was not affected by the optic design, but statistical analysis showed that one-piece, all-PMMA IOL construction provided the most consistent centration.     

Posterior chamber intraocular lens in the anterior chamber

BACKGROUND: The choice of design for intraocular lenses (IOLs) mainly depends on the selected location for the implant. HISTORY AND SIGNS: We report the case of dislocation of a foldable open-loop posterior chamber IOL into the anterior chamber during retinal detachment surgery. After several vitreoretinal interventions visual acuity was hand movements. THERAPY AND OUTCOME: The IOL remained in the anterior chamber without complications such as IOP rise or endothelial decompensation for several years. CONCLUSIONS: Foldable open-loop posterior chamber IOLs can be left in suitable anterior chambers for years without complications such as rise of intraocular pressure or corneal endothelial damage. Repeated measurements of endothelial cell density can provide an informative basis for the operative removal of this lens.     

Comparison of the cellular response on intraocular lenses implanted in rabbit eyes with and without extracapsular lens extraction

Three-piece poly(methyl methacrylate) intraocular lenses (IOLs) were implanted in rabbit eyes with and without lens extraction to examine the cellular response on the IOL surface without the effects of the residual lens cortex. Each rabbit had extracapsular lens extraction (ECCE) with IOL implantation in the posterior chamber of one eye. In the second eye, the IOL was implanted in the anterior chamber without lens extraction. The lenses were removed and studied with light microscopy and scanning electron microscopy one week after surgery. Light microscopic findings revealed a similar cellular response on the surface of the IOLs in both groups. Scanning electron microscopy suggested that the cellular adhesiveness on the IOL surface in the eyes without lens extraction was weaker than in the eyes that had ECCE. Cells on the IOLs in the eyes without lens extraction were flatter and had membranous pseudopodia. It appears that the cells on the IOL surface were caused by a foreign body reaction and that their adhesiveness to the IOL was affected by residual lens cortex.     

Cause of intraocular lens removal

To determine the rates of and reasons for removal of intraocular lenses (IOLs) during the first 6 years of implant surgery at Halifax Infirmary Hospital, we reviewed the medical records of all patients who underwent primary cataract extraction with IOL implantation and subsequent removal of the IOL between 1980 and 1985. Among 2482 patients 21 cases of secondary explanation (0.8%) were identified. Of the 21 IOLs 20 were anterior chamber lenses and 1 was a posterior chamber lens. The most frequent causes of IOL removal were suspected bacterial endophthalmitis, excessive lens movement due to poor fit and traumatic dislocation of the lens.     

Intraocular lenses for the correction of refraction errors. Part 1: phakic anterior chamber lenses

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.