Anterior chamber lenses. Part II: A laboratory study

Angle-supported intraocular lens versus scleral-sutured posterior chamber intraocular lens in post-cataract surgery aphakic patients: two-year follow-up cost-effectiveness analysis

PURPOSE

To compare visual, anatomical and economical outcomes of patients with secondary anterior chamber intraocular lens (AC-IOL) implantation and secondary scleral fixated intraocular lens (SF-IOL) implantation.

METHODS

In this retrospective observational study, 38 aphakic patients after complicated phacoemulsification divided in two groups, AC-IOL group (17 patients receiving AC-IOL implantation) and SF-IOL group (21 patients receiving SF-IOL implantation). Corrected distance visual acuity (CDVA), patient reported visual outcome (VF-14) and endothelial cell density (ECD) were measured at baseline and two-year follow-up. Complication rate was registered. The global cost of each procedure and the incremental cost-effectiveness ratio (ICER) were calculated.

RESULTS

No statistically significant difference was found in CDVA (logMAR 0.24 ± 0.17 vs. 0.32 ± 0.26, p = 0.27), VF-14 (68 ± 18 vs. 61 ± 20, p = 0.24), ECD (1456.48 ± 525.15 vs. 1341.71 ± 374.33, p = 0.48) and overall complication rate (p = 0.79) postoperatively between the SF-IOL group and the AC-IOL group. The ECD loss rate was significantly higher in the AC-IOL group (15.5% vs. 3.5%, p = 0.004). The average global cost of the two procedures was higher in the SF-IOL group (p < 0.005) and ICER showed an additional payment of 693 € for each patient in SF-IOL group against a saving of 186 endothelial cells 2 years postoperatively.

CONCLUSION

AC IOL and SF-IOL implantation showed similar outcomes in terms of visual function and safety profile. Higher ECD loss was found in AC-IOL group. The global cost of implantation was significantly lower for AC-IOL, but the ICER seems to justify the SF-IOL implantation in patients with low ECD.

A spontaneous protruded angle-supported anterior chamber intraocular lens: A case report

RATIONALE

Anterior chamber intraocular lens (ACIOL) remains a surgical option for visual rehabilitation during complicated cataract surgeries with minimal or no capsular support. ACIOL causing scleral perforation is rare, and the involved causes remain debatable.

PATIENT CONCERNS

Here, we present the case of a 62-year-old female with spontaneous protrusion of an angle-supported ACIOL haptic tip through an extracapsular cataract extraction (ECCE) wound, who presented with progressive right-eye ptosis and right-side headache.

DIAGNOSIS

The slit lamp examination showed a vertically aligned angle-supported Kelman Multiflex ACIOL in the anterior chamber. The ACIOL had deviated upward, with upper haptic protruding from the previous ECCE scleral tunnel wound. Fundus examination and optical coherence tomography (OCT) revealed cystoid macular edema (CME) with mild epiretinal membrane (ERM).

INTERVENTIONS

The patient was treated with ACIOL extraction, pars plana vitrectomy, ERM peeling, and scleral-fixated posterior chamber IOL implantation.

OUTCOMES

Three months after surgery, the best-corrected visual acuity in the right eye improved to 20/80 and the right-side headache and hyperemia of the conjunctiva had significantly subsided. Repeated OCT revealed improved CME.

LESSONS

Poor construction of the scleral tunnel incision may cause wound dehiscence. The vertically aligned ACIOL haptic tip resting at the angle may exert stress toward the dehiscent wound, exacerbating tissue erosion and causing scleral perforation with haptic tip exposure.

The Fate of Eyes with Anterior Chamber Intra-Ocular Lenses

A total of 143 anterior chamber (AC) intra-ocular lenses (IOL) of various designs were implanted in a five-year period and followed for 18 to 76 months. The lenses were inserted as a secondary implant after extracapsular cataract extraction (ECCE) complicated by vitrectomy, or after primary intra-capsular extraction. The complications (corneal edema, uveitis/glaucoma, extrusion/imbedding, cystoid macular edema), the final visual acuity and the need for removal of the IOL were analyzed. Only small differences were found between the different lenses but some association was found between complicated surgery (ECCE + vitrectomy) and a higher rate of complication, poorer visual outcome and more frequent need for IOL removal. Cystoid macular edema was encountered only in cases with complicated ECCE. A high percentage of other ocular pathologies was found among the cases, possibly implying that diseased eyes are more prone to surgical complications. An alternative to the AC-IOL in cases with a ruptured posterior capsule is the suture-supported posterior chamber IOL, but the flexible-loop AC-IOL may not yet be obsolete.

Anterior chamber fixation of a posterior chamber intraocular lens: a novel technique

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

Severe endothelial cell loss with anterior chamber phakic intraocular lenses

We report the case of a highly myopic patient who developed severe bilateral endothelial cell loss following implantation of 2 angle-supported anterior chamber pIOL models, the Acrysof Cachet and the GBR (currently off the market).

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Modern cataract surgery: unfinished business and unanswered questions

We summarize information, based on clinicopathologic studies over the past decade, on various cataract intraocular lens (IOL) procedures and modern "specialized" IOLs, that will help surgeons continuously improve long-term results for cataract patients. Although most operations do initially provide excellent refractive correction and visual rehabilitation, late complications occur. These sometimes are missed because they are outside of the routine period of follow-up care. We have tried to determine if the various techniques and IOLs truly deliver the long-term results that we desire. Most safety and efficacy information is derived from the manufacturer and is passed through the U.S. Food and Drug Administration (FDA). This is often based on limited, relatively short-term observations made by the manufacturer. After a lens receives FDA approval, there are few means to assess the outcome of each procedure and lens years later. We rarely hear of a 10- or 20-year follow-up study. We have found that one of the best means to assess long-term results is pathologic analyses. We discuss recently studied aspects of pathologic reactions, such as posterior capsule opacification, intracapsular fibrosis, glistenings, intralenticular opacification, and other issues with the various IOL platforms; we then present a clinicopathological overview of tissues and IOLs from our database. These include hydrophobic and hydrophilic acrylic designs, plate lenses, and a dual optic lens.

Endophthalmitis due to exposure of anterior chamber intraocular lens haptic tip

After bilateral implantation of an angle-supported anterior chamber intraocular lens (AC IOL) in an allergic patient, the haptic tips were exposed through the limbus in the left eye. Endophthalmitis developed in the eye and was treated by pars plana vitrectomy, IOL extraction, and intravitreal antibiotic injection. Haptic repositioning was performed in the right eye. In this report, we assess the possibility that exposure of the angle-supported AC IOL haptics caused the endophthalmitis. We hypothesized that vigorous rubbing of the eye of the atopic patient might cause limbal erosion that could lead to exposure of the angle-supported AC IOL haptic through the limbus.

Pseudophakic corneal edema: A review of mechanisms and treatments

PURPOSE

To review the pathological mechanisms and treatments for pseudophakic corneal edema (PCE), one of the most common indications for penetrating keratoplasty.

METHODS

The literature was examined for the molecular biology associated with PCE and for the surgical and medical treatments for this disorder.

RESULTS

The incidence of PCE has recently been decreasing because of improved surgical instrumentation, including improvements in intraocular lens designs that cause less trauma to the corneal endothelium. Extracellular matrix and growth factor abnormalities occur in PCE corneas and recently, the role of aquaporins, which are involved in the regulation of fluid movement across cells, has been investigated.

CONCLUSIONS

Although newer treatment options have been suggested, penetrating keratoplasty still remains the most definitive treatment and has the highest success rate.

Long-term endothelial changes after implantation of anterior chamber intraocular lenses in cataract surgery

PURPOSE

To determine and quantify corneal endothelial damage after primary or secondary implantation of anterior chamber intraocular lenses (AC IOLs).

SETTING

Eye Clinic, University of Trieste, Trieste, Italy.

METHODS

This retrospective study comprised 125 patients who had implantation of an AC IOL from January 1987 to December 1998. The mean follow-up was 5.2 years. The IOLs were the Domilens Chiron Vision Z (n = 52), the Iolab U85J (n = 38), and the AMO AC51B (n = 35). The Konan specular microscope was used to perform full morphometric analysis of the corneal endothelium. The values obtained were compared with those in fellow eyes, which were phakic or pseudophakic with a posterior chamber IOL (PC IOL). Two years later, 63 patients (mean follow-up 2.1 years) had another morphometric analysis and the values obtained were compared with those in the same eye at the previous examination. The Student t test for unpaired groups was used to compare the results at a 5% significance level.

RESULTS

The mean endothelial cell density (ECD) was significantly lower in eyes with primary or secondary AC IOL implantation than in unoperated phakic eyes (P<.01). Patients who had primary AC IOL implantation in 1 eye and PC IOL implantation in the fellow eye had a difference in ECD that was not statistically significant. The endothelial cell difference was significantly greater in aphakic patients who had a secondary AC IOL implantation (P<.05). The ECD ranged from 1015 to 2980 cells/mm(2). The endothelium in the various groups showed no significant changes in the coefficient of variation (CV) in cell size. The ECD and endothelial CV in the same eyes at the second examination were not significantly different from the values 2 years previously.

CONCLUSIONS

Anterior chamber IOL implantation did not appear to alter corneal endothelial function. Results indicate that the endothelial cell loss was related to surgical trauma rather than the presence of an IOL in the anterior chamber.

Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology

OBJECTIVE

This review was conducted to determine the safety and efficacy of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber intraocular lenses (IOLs) in eyes with inadequate capsular support for posterior chamber implantation in the capsular bag or ciliary sulcus. It also attempted to determine whether there is a preferred IOL or fixation site of choice in eyes with inadequate capsular support.

METHODS

A literature search conducted for the years 1980 to 2001 yielded 189 citations related to IOL implantation in the absence of capsular support. An update search, conducted in March 2002, yielded an additional 28 articles. The Anterior Segment Panel members reviewed these abstracts and selected 148 articles of possible clinical relevance for review. Of these, 89 were considered sufficiently clinically relevant for the panel methodologist to review and rate according to the strength of evidence. A level I rating was assigned to properly conducted, well-designed, randomized clinical trials; a level II rating was assigned to well-designed cohort and case-control studies; and a level III rating was assigned to case series. Articles comparing the safety and efficacy of the IOL type and fixation site were further evaluated for the quality of the statistical methods used in the study. Studies with a rating of A or B were considered acceptable, C was borderline, and D and F were considered unacceptable as medical evidence.

RESULTS

Forty-three articles with data concerning outcome of IOL insertion in eyes with inadequate capsular support had an evidence rating of level III or higher and were used in the final review of the safety and efficacy of one or more lens types and/or fixation sites. Seven articles had data about more than one lens type. Six had a statistical method rating of C or higher and were used to evaluate differences in visual outcomes and complication rates between lens types and fixation sites.

CONCLUSIONS

The literature supports the safe and effective use of open-loop anterior chamber, scleral-sutured posterior chamber, and iris-sutured posterior chamber IOLs for the correction of aphakia in eyes without adequate capsular support for placement of a posterior chamber lens in the capsular bag or ciliary sulcus. At this time, there is insufficient evidence to demonstrate the superiority of one lens type or fixation site. Precise determination of small differences in visual outcome or complication rates will require a large prospective, randomized clinical trial.

Retrospective evaluation of intraocular lenses in adults younger than 60 years

Data from the U.S. Food and Drug Administration, the American Academy of Ophthalmology's National Eyecare Outcomes Network, and Storm Eye Institute databases were analyzed for short- and long-term safety and efficacy outcomes of intraocular lens (IOL) implantation in adults younger than 60 years and 60 years and older. Statistical analyses for significance were performed where appropriate. A comprehensive literature review was conducted to identify safety and efficacy outcomes and their relationship to patient age at the time of implantation. Analyses established that the performance of IOLs in adults younger than 60 years was comparable to that in adults older than 60 years and supported the use of IOLs in the younger adult population.

Bipseudophakia: clinicopathological correlation of a dropped lens

PURPOSE

To examine postmortem human globes containing an anterior chamber and a posterior chamber intraocular lens (IOL).

SETTING

Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Charleston, South Carolina, USA.

METHODS

The globes were sectioned at the equator, and the anterior and posterior segments were macroscopically examined. Gross photographs were taken using the Miyake-Apple posterior photographic technique. Histological sections were cut and stained with hematoxylin and eosin, periodic acid-Schiff, and Masson's trichrome.

RESULTS

Histopathological findings included a large Soemmering's ring, a tear in the posterior capsule, 1 haptic of the anterior chamber IOL displaced into the iridectomy, thin and atrophic corneal epithelium, separation of Bowman's layer and stroma by fibrovascular tissue, and atrophy of the retinal ganglion cell layer and nerve fiber layer.

CONCLUSION

In cases in which secondary IOL implantation is indicated, removing the dislocated IOL appears to be a reasonable choice.

[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.

Pars plana vitrectomy and sutured posterior chamber lens implantation

Transcleral suturing of posterior chamber intraocular lenses (IOLs) was developed to extend the benefits of IOL visual rehabilitation to eyes lacking capsular support and to avoid the complications of closed loop interior chamber IOLs. Although most frequently implanted after complicated cataract surgery or penetrating keratoplasty, they are indicated in several situations following pars plana vitrectomy. The surgical techniques have evolved to minimize the risk of complications, but the surgery remains technically more demanding and time-consuming than insertion of a modern open loop anterior chamber IOL. No randomized trials have compared the relative risks of each lens type, which leaves surgeon preference as the major determinant of what lens is implanted. It is likely, however, that in eyes with extensive anterior chamber angle damage or large iris defects, sutured posterior chamber IOLs will remain the first choice for surgical rehabilitation.

Long-term follow-up of leiske closed-loop anterior chamber intraocular lenses

PURPOSE

To provide long-term follow-up on the rates of endothelial cell loss in eyes with retained closed-loop anterior chamber intraocular lenses (IOLs).

SETTING

Private practices, Chicago, Illinois, USA.

METHODS

In 1980 to 1982, 3 surgeons performed 587 intracapsular cataract extractions with implantation of Leiske closed-loop anterior chamber IOLs. During the prospective part of the study from 1991 to 1996, 59 patients with 83 eligible eyes were followed using specular microscopy and pachymetry. The mean follow-up of the prospective study was 41.9 months, or 12.9 years from the original cataract surgery.

RESULTS

No specific preoperative or postoperative factor except the behavior of the fellow eye (P =.022) predicted the rate of endothelial cell loss. During the prospective study, 6 patients required IOL exchange and corneal transplantation. The rate of corneal decompensation was heavily dependent on the initial measurement of endothelial cell density. Corneas with initial endothelial cell counts greater than 1000 cells/mm(2) had a decompensation rate of 1.5%, and corneas with counts of 500 cells/mm(2) or less had a decompensation rate of 57.1% (P <.01).

CONCLUSIONS

Clinical examination and serial measurements of endothelial cell density provide the most reliable methods for monitoring patients with closed-loop anterior chamber IOLs. Endothelial cell counts can predict the rate of corneal decompensation. Patients with endothelial cell counts greater than 1000 cells/mm(2) usually do not require an IOL exchange.

The South Asian cataract management study: complications, vision outcomes, and corneal endothelial cell loss in a randomized multicenter clinical trial comparing intracapsular cataract extraction with and without anterior chamber intraocular lens implantation

OBJECTIVE

To determine clinical outcomes of primary intracapsular cataract surgery with and without implantation of anterior chamber lenses.

DESIGN

A multicenter randomized clinical trial.

PARTICIPANTS

One thousand two hundred twenty-nine male and female patients 40-75 years of age with senile cataract.

METHODS

Study patients were recruited from screening eye camps and outpatient clinics. Randomization to the two treatment groups was performed after screening for predetermined inclusion and exclusion criteria. Demographics, visual acuity, intraocular pressures, and corneal endothelial cell data were recorded before surgery and at 6 weeks, 12 months, and 24 months after surgery. Monitoring of the study was secured by a standardized image documentation procedure on all patients using the IMAGEnet digital imaging system. Analysis of corneal endothelial cell images was performed with the Cell Soft software (Topcon Corporation, Japan).

MAIN OUTCOME MEASURES

Visual acuity and central corneal endothelial cell loss.

RESULTS

The patients were randomized to intraocular lens (IOL; n = 616) and no IOL (n = 613) implantation. Surgical complications were reported in 177 (14.4%) patients (IOL = 14.8%; no IOL = 14.0%). The most frequent complication observed was vitreous loss which occurred in 10.3% of eyes (IOL = 11.2%; no IOL = 9.5%). At the final examination (2 years after surgery), 88% of the operated eyes had a best corrected vision of 6/18 or better (IOL = 88.8%; no IOL = 86.6%). Analysis of corneal endothelial cell data showed a small but significantly greater cell loss 6 weeks after surgery in eyes with IOL compared with those without IOL, but no overall difference was found between the treatment groups in the long term follow-up.

CONCLUSIONS

The findings indicate that there is a rationale for the use of anterior chamber intraocular lenses in primary intracapsular cataract surgery.

Is anterior chamber lens implantation after intracapsular cataract extraction safe in rural black patients in Africa? A pilot study in KwaZulu-Natal, South Africa

PURPOSE

There are an estimated 16 million people blind from cataract world-wide. In many areas the routine operation is intracapsular cataract extraction (ICCE). The role of modern anterior chamber (AC) intraocular lenses (IOLs) is being explored, and they have been shown to be safe and successful in Asia. Are they equally safe in rural black African populations?

METHODS

One hundred black patients aged 50 years and over who attended Edendale Hospital were enrolled in a pilot study of insertion of AC IOLs after ICCE. They were followed up for 6 months.

RESULTS

With financial remuneration, the follow-up rate at 8 weeks increased from the usual 30% to 72%. At 6 months, 67% of eyes achieved a correlated visual acuity of 6/18 or better. Thirty per cent had persistent uveitis, 16% had peripheral anterior synechiae beyond the points of haptic contact, and 5% had an intraocular pressure greater than 21 mmHg.

CONCLUSIONS

A randomised trial comparing ICCE with AC IOL and extracapsular cataract extraction with posterior chamber IOL is probably not justified at this time in this population. However, there may be wide variations in the reaction of the eyes of different African ethnic groups to IOLs. In view of the successful use of AC IOLs in Asian eyes, further pilot studies of AC IOLs may be warranted in other parts of Africa where ICCE is the routine procedure.

Long-term follow-up of primary anterior chamber intraocular lens implantation

PURPOSE

To evaluate the long-term outcome in eyes having primary anterior chamber intraocular lens (AC IOL) implantation.

SETTING

Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan.

METHODS

Primary AC IOL implantation was performed in 171 eyes from 1983 to 1988. Two lenses were implanted: the open C-loop Simcoe lens and the 4-point fixation Kelman lens. In 86 eyes that had a mean follow-up of 9 years 7 months, visual acuity, corneal endothelial cell density, pupil shape, and the presence of associated complications were examined.

RESULTS

Although the final visual acuity was 0.5 or better in 60 eyes (69%), corneal endothelial cell density was less than 2000 cells/mm2 in 46 eyes (57%). Postoperative complications included a deformed pupil in 48 eyes (56%) and bullous keratopathy in 12 eyes (14%). In 14 eyes the AC IOL was explanted; 11 of these were the open C-loop Simcoe lens.

CONCLUSION

Although our findings show that the open C-loop AC IOL (Simcoe) is contraindicated, implantation of the 4-point fixation AC IOL may be acceptable in selected cases.

Uveitis-glaucoma-hyphema syndrome after handmade, anterior chamber lens implantation

Two patients developed uveitis-glaucoma-hyphema syndrome secondary to implantation of handmade anterior chamber intraocular lenses (IOLs). The IOLs were designed and made by the patients' ophthalmologists in their native Ukraine. The cases illustrate innovative and unusual solutions to the shortage of quality IOLs in the developing world and the challenging management of patients who present with complications arising from these IOLs.

Randomised controlled trial of anterior-chamber intraocular lenses

BACKGROUND

There are an estimated 16 million people blind in both eyes with cataracts. Most live in rural areas of developing countries where surgical resources are scarce. There is no consensus on the most appropriate type of intraocular lens in situations where high-volume low-cost surgery is required. This study was undertaken to evaluate the safety of multiflex open-loop anterior-chamber lenses (ACIOLs).

METHODS

2000 people attending Lahan Eye Hospital, southern Nepal, with bilateral cataracts reducing vision to 6/36 or less were randomly allocated to receive standard surgery--intracapsular extraction (ICCE) with aphakic correction--or ICCE with an ACIOL in their first operated eye. The primary outcome was a visual acuity of less than 6/60 in the operated eye at 1 year follow-up. Visual acuity was measured for 91% of the cohort at 1 year. The sample size was estimated to detect a doubling in poor visual outcome from an estimated rate of 4% in the standard surgery (control) group.

FINDINGS

The median (range) time taken to do the surgery was 6.0 (3.0-17.2) min for the ACIOL group and 4.1 (2.4-10.3) min for the control group. 1 year after surgery, 5.0% of the ACIOL group and 5.4% of controls had functional vision less than 6/60 (OR 0.93 [0.60-1.43], p = 0.71). The causes of poor vision in the ACIOL and control groups were: correctable refractive error (22 and 29), uveitis/secondary glaucoma (13 and two), endophthalmitis (four and seven), pre-existing eye disease (four and five), retinal detachment (none and four), cystoid macular oedema (two and none), corneal ulcer (one and one), and corneal decompensation (none and one).

INTERPRETATION

This study provides evidence that, in rural areas of developing countries, multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction. Further follow-up is planned.

Ultrasound Biomicroscopy of Baikoff Anterior Chamber Phakic Intraocular Lenses

BACKGROUND

The purpose of the study was to analyze qualitatively and quantitatively anatomic relationships of anterior chamber Baikoff phakic intraocular lenses (IOL) to the cornea, angle, iris, and lens in myopic eyes.

METHODS

Thirteen phakic myopic eyes (-9.00 to -15.00 diopters) corrected by minus power, angle-supported, anterior chamber intraocular lenses of the ZB5M style (Chiron-Domilens), with a mean follow-up of 25 months (range 18 to 36 months), were examined clinically and by ultrasound biomicroscopy.

RESULTS

The mean distance (+/- SD) between the central cornea and the IOL was 2.05 +/- 0.18 mm (range 1.8 to 2.47 mm); mean distance between the corneal periphery and the IOL was 1.56 +/- 0.17 mm (range 1.33 to 1.95 mm); and the mean distance between the IOL and the lens was 0.58 +/- 0.12 mm (range 0.48 to 0.81 mm). IOL footplates seemed to be correctly positioned in the angle in all eyes. We observed no goniosynechiae. In six eyes, we found localized posterior indentation of the iris caused by the haptics. Four of these six eyes exhibited oval pupils associated with an oversized IOL.

CONCLUSIONS

High frequency ultrasound biomicroscopy can define anatomic relationships of anterior chamber phakic IOLs, and help analyze the mechanisms of corneal and iris complications.

Combined pars plana vitrectomy-lensectomy and open-loop anterior chamber lens implantation

PURPOSE

To investigate the effectiveness of open-loop, one-piece, flexible, Kelman-style, all-polymethylmethacrylate (PMMA) anterior chamber intraocular lenses (AC IOLs) in patients undergoing pars plana vitrectomy surgery for a variety of vitreoretinal disorders.

METHODS

Fifteen patients (6 women and 9 men) underwent combined pars plana vitrectomy with insertion of an open-loop AC IOL. Postoperative results were evaluated.

RESULTS

The average preoperative visual acuity of 20/360 (logMAR scale, 1.25 +/- 0.80) improved to 20/52 (logMAR scale, 0.42 +/- 0.35) after an average follow-up of 10.2 months (range, 1-41 months). Of 15 eyes, 7 (47%) achieved a visual acuity of better than 20/40. There was no evidence of glaucoma exacerbation or corneal decompensation. Visual acuity was limited primarily by chronic cystoid macular edema in 4 (27%) of 15 eyes.

CONCLUSION

In this preliminary series of patients, open-loop, flexible, all-PMMA, Kelman-style AC IOLs appear to be well tolerated and represent a viable, simple alternative to transscleral fixation of a posterior chamber IOL or surgical aphakia in patients undergoing vitrectomy surgery.

Are there acceptable anterior chamber intraocular lenses for clinical use in the 1990s? An analysis of 4104 explanted anterior chamber intraocular lenses

PURPOSE

The authors pose the question as to whether there are any anterior chamber intraocular lenses (AC IOLs) acceptable for clinical use in the 1990s.

METHODS

Data on the incidence and types of complications of 4104 AC IOLs that were submitted to the Center for IOL Research from 1982 to 1993 were retrieved from the laboratory database and analyzed using cumulative frequency calculations and the chi-square test. Normalized explantation rates were related to implantation rates that were derived from market-share analysis.

RESULTS

Of 4104 explanted IOLs, 50% were closed-loop designs (n = 2095/4104); 26% (1100/4104) were miscellaneous, older designs; and 22% (919/4104) were open-loop lenses. The most important complications were corneal pathology (2065/4104) and inflammation (1370/4104). Closed-loop designs were responsible for almost 80% of corneal pathology, with an increasing complication rate with ongoing implant duration (P < 0.0001). Open-loop AC IOLs showed, in relation to their normalized rate of implantation, a significantly lower rate of complications and explantations (P < 0.01).

CONCLUSION

Complication rates of flexible, open-loop AC IOLs are much lower than previously assumed. They should be distinguished clearly from most older AC IOL designs. Consideration of these lenses as an alternative to sutured posterior chamber IOLs for secondary or exchange implantation may be warranted for selected clinical indications. They also could provide an alternative to the aphakic spectacle rehabilitation program in developing countries, which will have a positive impact on the overwhelming backlog of patients with cataract in the underprivileged world.

Intraocular complications associated with the Dubroff anterior chamber lens

We examined a series of 53 consecutive eyes form which Dubroff-style anterior chamber lenses were explanted. The mean time from implantation to explantation was 46.21 months (range six to 99 months). Problems leading to explantation included bullous keratopathy (83%), glaucoma (51%), chronic cystoid macular edema (40%), and iritis (13%). Molteno valves were required in 9% of eyes. Progressive anterior synechias resulted in intraocular lens displacement against the cornea in 19%. The Dubroff lenses caused problems similar to those previously observed with closed-loop anterior chamber lenses but had a higher incidence of severe glaucoma and progressive peripheral anterior synechias.

Intraocular lens exchange for anterior chamber intraocular lens-induced corneal endothelial damage

BACKGROUND

Anterior chamber and iris-plane intraocular lenses (IOLs) have been implicated in causing corneal endothelial damage and progression to pseudophakic bullous keratopathy.

METHODS

The authors performed IOL exchanges on 102 eyes with signs of early corneal decompensation or progressive endothelial cell loss associated with these anterior chamber or iris-plane IOLs. Replacement IOLs were posterior chamber lenses sutured to the iris (87 eyes), sutured to the sclera (3 eyes), or placed in the ciliary sulcus (12 eyes).

RESULTS

Seventy-two eyes (71%) had the same or improved vision after a mean follow-up period of 18.6 months (range, 6 to 60 months). Only 24 eyes (23.5%) progressed to corneal decompensation. Of the eyes that decompensated, 75% had preoperative endothelial cell counts of 500 cells/mm2 or less (P < 0.0001), and 83% had preoperative signs of early corneal decompensation (P < 0.001). Biomicroscopic signs of early corneal decompensation seen preoperatively in 50 eyes resolved in 17 eyes (34%) and remained unchanged in 12 eyes (24%) at the last postoperative follow-up visit.

CONCLUSION

Removal of anterior chamber and iris-plane intraocular lenses in eyes showing signs of endothelial damage may prevent progression to pseudophakic bullous keratopathy if performed before a critical degree of endothelial cell loss or dysfunction has developed.

Indications for and results of a large series of intraocular lens exchanges

We conducted a retrospective review of 79 patients who had intraocular lens (IOL) explantation and exchange over a 12-year period. Seventy-nine eyes of 40 males and 39 females from 17 to 94 years of age were followed from three months to more than 12 years. Sixty-one percent (61%) were posterior chamber lenses and 39% were anterior chamber lenses replaced by 76% posterior chamber and 24% anterior chamber lenses. The indications for lens exchange were eccentric or displaced IOL (41.7%), endothelial decompensation (27.7%), incorrect IOL power (12.6%), and uveitis-glaucoma-hyphema syndrome (10.0%). Analysis of the clinical results revealed that 72% of the cases had postoperative visual acuity better than or equal to 20/30, and 8% had a loss of one or more lines of visual acuity. Among the complications occurring after IOL exchange were retinal detachment, glaucoma, corneal decompensation, and anisometropia.

Changing trends in explanted intraocular lenses: a single center study

Over a nine-year period, our practice removed 1,091 intraocular lenses. The most common type of lens requiring explantation was the closed-loop anterior chamber lens (58.6%). The Stableflex lens represented the largest percentage of all removed lens types (28.8%). The number of closed-loop anterior chamber lenses requiring removal peaked in 1988 and then gradually declined. All other lens styles have shown gradually increasing removal rates. Older style iris-fixated lenses and rigid anterior chamber lenses, which have not been implanted for several years, have increasing removal rates. Late breakage of fixational polypropylene sutures with pupil-supported iris-fixated lenses have occurred in five cases; the average time from implantation to suture breakage was 112 months.

Penetrating keratoplasty and transscleral fixation of posterior chamber lens

We reviewed the outcome in 115 patients who underwent penetrating keratoplasty and transscleral fixation of a posterior chamber lens. One patient died soon after surgical procedures, and nine patients were lost to follow-up, leaving a cohort of 105 patients. Mean follow-up time was 26.8 months (range, six to 43 months). Visual acuity of 20/40 or better was found in 29 patients (27.6%) and 20/50 to 20/200 in 37 patients (35.2%). Reasons for poor visual outcome included cystoid macular edema in ten patients (9.5%), age-related macular degeneration in six patients (5.7%), and retinal detachment in four patients (3.8%). None of the patients developed lens decentration. There were no instances of hyphema and only one patient had a perioperative limited suprachoroidal hemorrhage. New-onset increase in intraocular pressure developed in 20 of 66 patients (30.3%). Analysis of the 39 patients with preoperative increase in intraocular pressure that required medical treatment demonstrated an improvement in 13 patients (33.3%), worsening in 12 patients (30.8%), and unchanged status in 14 patients (35.9%). The exposed haptic suture was covered by using one of the following three alternative methods: a conjunctival flap, a scleral flap, or a corneal tissue button. Exposure of the haptic suture through the conjunctiva was a complication in 21 patients (20%). Of these 16 (76.1%) occurred in the group with a conjunctival covering, five (23.8%) occurred in the group with a scleral flap, and none occurred in the corneal tissue button group. This study demonstrated that transscleral fixation of a posterior chamber lens is a viable option in the treatment of patients undergoing penetrating keratoplasty and intraocular lens implantation with absent capsular support.

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 1981-1988: clinical indications and pathologic findings

We analyzed 740 penetrating keratoplasty specimens received at the Intermountain Ocular Research Center from 1981 through 1988. These corneal specimens were categorized by clinical indications for removal and pathologic confirmation of the clinical findings. Keratoconus was the most common indication for a penetrating keratoplasty (22.8%). This was closely followed by pseudophakie bullous keratopathy (21.8%), regraft (13.2%), scarring (8.9%), aphakic bullous keratopathy (6.4%), and Fuchs' endothelial dystrophy (5.8%). Since 1984, pseudophakic bullous keratopathy has surpassed keratoconus as the most common indication for penetrating keratoplasty (27.3% vs. 20.2%). Pseudophakic bullous keratopathy was found more commonly than keratoconus in each of the last four years of this study. The most common type of intraocular lens associated with pseudophakic bullous keratopathy was an anterior chamber lens (52.8%), with iris-fixated (26.7%) and posterior chamber (17.4%) lenses seen less frequently.

An analysis of flexible anterior chamber lenses with special reference to the normalized rate of lens explantation

A survey of 1204 closed-loop anterior chamber intraocular lenses (AC-IOLs) and 310 open-loop AC-IOLs accessioned between November 1982 and January 1990 was conducted at the Center for Intraocular Lens Research. An analysis of complication rates was done after normalization of data with respect to market share totals. The results establish that an unacceptable complication rate is associated with the closed-loop design when compared with either the tripod or quadripod lens styles. Furthermore, the closed-loop designs, while comprising an estimated 45% of the total number of AC-IOLs estimated to be implanted in the United States (n = 674,000), were responsible for 80% of the AC-IOLs explanted after complications and accessioned at the authors' center. A rethinking of the extreme condemnation of all anterior chamber IOLs that has surfaced in recent years is warranted. This is particularly true with respect to indications for use of sutured posterior chamber (PC) IOLs as well as with regard to possible use of open-loop AC-IOLs in less-industrialized nations.

Refractive surgery for high myopia. The Worst-Fechner biconcave iris claw lens

Surgical correction of high myopia is indicated in a limited number of cases. Techniques include (epi)keratophakia, keratomileusis and implantation of a negative-power IOL. The iris claw lens, fixed to the midperiphery of the iris, has proved its safety in aphakic eyes. The model has been adapted by giving it a vault in order to make it suitable for implantation in high myopic phakic eyes. The implantation technique and short-term results of patients operated by Worst are presented.

Complications of sulcus-supported intraocular lenses with iris sutures, implanted during penetrating keratoplasty after intracapsular cataract extraction

In a retrospective study, the authors analyzed visual results and postoperative complications in a series of 14 consecutive patients who had undergone penetrating keratoplasty and implantation of a posterior chamber intraocular lens (PC IOL) in the absence of the posterior capsule. Seven patients suffered from aphakic bullous keratopathy and seven from pseudophakic bullous keratopathy. Postoperative follow-up was 7.6 months on the average. Best-corrected postoperative visual acuity was 20/60 or better in four cases and 20/200 or better in eight. Glaucoma was present before surgery in four eyes, which persisted in all cases and developed in four new cases. Results of gonioscopic examination showed the postoperative development of goniosynechiae in four eyes. Pseudophakodonesis of various extent was present in ten eyes. Preoperatively, cystoid macular edema was diagnosed angiographically in one case. It did not improve after surgery and was seen in three additional eyes postoperatively. Causes for postoperative visual acuity lower than 20/200 were cystoid macular edema in three cases, graft rejection in one case, central retinal scar in one case, and optic nerve atrophy in one case. A distortion of the pupil was seen in three eyes in miosis and in four additional eyes in mydriasis. Corneal thickness as well as anterior chamber depth were within normal limits. Fluorophotometric evaluation of the blood-aqueous barrier showed values comparable with those obtained after intracapsular cataract extraction and implantation of an iris-fixated IOL. Despite the relatively good visual results, the high postoperative incidence of cystoid macular edema and/or glaucoma may discourage the use of this technique.

Natural history of cystoid macular edema in pseudophakic bullous keratopathy

A retrospective review of 25 consecutive patients having penetrating keratoplasty (PKP) with the preoperative diagnoses of pseudophakic bullous keratopathy (PBK) and cystoid macular edema (CME) was undertaken to analyze the natural history of preoperative CME following keratoplasty. Follow-up ranged from 13 to 54 months with a mean of 27 months. All patients had intraocular lens exchanges with 24 receiving posterior chamber lenses; 23 had lenses sutured to the posterior iris. Sixteen patients (64%) recovered a visual acuity of 20/40 or better. The average time for visual recovery to 20/40 was nine months with a range of two to 45 months. Eighteen (72%) had resolution of angiographic CME. Three patients previously diagnosed as having chronic CME recovered visual acuity of 20/40 or better. Cases of PBK with CME may have an excellent visual prognosis if the IOL is managed properly at the time of PKP.

Intraocular lens implantation in phakic rabbit eyes

Three sizes (13.5 mm, 17.5 mm, and 18.5 mm) of open loop, one piece, poly(methyl methacrylate) anterior chamber intraocular lenses (IOLs) were implanted in 12 phakic rabbit eyes to evaluate the effect of the IOL on the crystalline lens and the anterior chamber. Six eyes were used as a control group. Minimum follow-up was four weeks. All the IOLs touched the crystalline lenses, and on the first postoperative day, round subcapsular lens opacities were found in all eyes in the area of IOL contact. The lens opacities became more dense with time. Only one eye in the control group showed a subcapsular opacity, which was linear rather than round. Anterior chamber inflammation was 1+ to 2+ in ten eyes (80%) in the IOL group during the first and second weeks, whereas minimal inflammatory changes occurred in the control group. These results suggest that with current IOL technology, IOL insertion in the phakic eye to correct refractive errors results in a high incidence of cataract if IOL-to-lens touch occurs.