Indications for and results of intraocular lens explantation

Indications and Outcomes of Intraocular Lens Explantation in a Tertiary Eyecare Center in Hungary between 2006 and 2020

Purpose

Our study aimed to evaluate the indications and outcomes of intraocular lens (IOL) explantation surgeries in a tertiary eyecare center in Hungary.

Materials and Methods

This retrospective study included all IOL explantation surgeries performed between 2006 and 2020 at the Department of Ophthalmology of Semmelweis University, Budapest, Hungary. There were no exclusion criteria for this study. For each patient, the demographics, clinical history, preoperative status, indications for IOL explantation, and operative and postoperative details were reviewed. Primary outcomes included explantation indications and the type of secondary implanted IOL.

Results

A total of 161 eyes from 153 patients were included (96 males; 62.7%); age at the time of the IOL explantation was 65.0 ± 17.4 years. The mean time between primary cataract surgery and IOL explantation was 8.5 ± 7.7 years. In total, 139 (86.3%) PCIOLs and 22 (13.7%) ACIOLs were explanted. The main indications for IOL explantation were dislocation (n = 133; 95.7%) and refractive cause (n = 2; 1.4%) in the PCIOL group. Among ACIOL explantations, the main reasons were pseudophakic bullous keratopathy (n = 14; 63.6%), dislocation (n = 4; 18.2%), and refractive cause (n = 2; 9.1%). In the PCIOL group, 115 (82.7%) primary IOLs were implanted in the capsular bag, 16 (11.5%) were sulcus fixated, and 8 (5.8%) were scleral fixated. The most frequent ocular comorbidities were previous vitrectomy (n = 50, 31.1%), previous ocular trauma (n = 45, 28.0%), glaucoma (n = 16, 9.9%), pseudoexfoliation syndrome (n = 15, 9.3%), and high axial myopia (n = 14, 8.7%). The most commonly used secondary IOL implant was the prepupillary iris-claw IOL (n = 115, 73.7%), followed by the retropupillary iris-claw IOL (n = 32, 20.5%). Uncorrected visual acuity (UCVA) was significantly better following IOL exchange in the entire sample (1.57 ± 0.61 (range: 2.40-0.05) vs. 0.77 ± 0.56 (range: 2.40-0.00); p < 0.001). Best-corrected visual acuity (BCVA) was maintained or improved in 80.7% of cases after IOL explantation.

Conclusions

The most common indication for IOL explantation at a tertiary eyecare center in Hungary is IOL dislocation, followed by pseudophakic bullous keratopathy. Prepupillary and retropupillary iris-claw IOL are the most frequently used secondary implants and their use resulted in a significant UCVA improvement following IOL exchange.

Changes in Intraocular Lens Explantation Indications and Comparison of Various Explantation Techniques

PURPOSE

To examine the current causes of intraocular lens (IOL) explantation, compare various IOL explantation techniques, and assess the visual outcomes and complications.

DESIGN

Retrospective comparative case series.

PARTICIPANTS

A total of 175 eyes of 160 patients who underwent IOL exchange for a one-piece foldable acrylic IOL between January 2010 and March 2022 were covered by the research. Group 1 included 74 eyes from 69 patients in which the IOL was removed after being grasped, pulled, and refolded inside the main incision. Group 2 consisted of 66 eyes from 60 patients in which the IOL was removed by bisecting it, whereas group 3 included 35 eyes from 31 patients in which the IOL was removed by enlarging the main incision.

MAIN OUTCOMES

Surgical indications, interventions, visual outcomes and refraction, and complications.

RESULTS

The mean patient age was 66.1 ± 10.5 years. The mean time between primary surgery and IOL explantation was 57.0 ± 38.9 months. IOL dislocation (in 85 eyes, 49.5%) was the most common reason for IOL explantation. When the patients were examined in terms of both surgical indication groups and IOL removal techniques, corrected-distance visual acuity increased significantly in all subgroups (P < .001). The increase in astigmatism after surgery was 0.08 ± 0.13 diopters (D) in group 1, 0.09 ± 0.17 D in group 2, and 0.83 ± 0.29 D in group 3 (P < .001).

CONCLUSIONS

The grasp, pull, and refold technique for IOL explantation provides a simpler surgery, less complication, and good visual outcomes.

Multifocal intraocular lens exchange to monofocal for the management of neuroadaptation failure

BACKGROUND

The aim of this study was to evaluate visual, refractive, quality of vision, visual function and satisfaction of multifocal intraocular lens (MF-IOL) exchange with a monofocal IOL (MNF-IOL) in dissatisfied patients following MF-IOL implantation.

METHODS

This was a retrospective case series. Bilateral IOL exchange (MF-IOL to MNF-IOL) was performed in 13 patients (26 eyes) with neuroadaptation failure. Questionnaires including the Quality of Vision (QoV), Visual Function Index (VF-14 and Rasch-revised VF-8R version), and a satisfaction questionnaire were used.

RESULTS

The mean time for IOL exchange was 15 months. The corrected distance visual acuity (CDVA) improved from 20/26 to 20/23 (P = 0.028). The uncorrected near visual acuity (UNVA) worsened after exchange from 20/47 to 20/62 (P = 0.024). QoV scores improved significantly across all three subscales after exchange. Visual function for far distance improved with a change in VF-14 score from 74.2 ± 24.8 to 90.9 ± 9.1 (P = 0.03). The VF-8R score showed worsening although not statistically significant. Near vision spectacle independence was totally or partially lost in all cases. Ten patients (77%) reported they would not repeat the lens exchange. Safety and efficacy indices changed from 1.23 to 0.85, respectively, at three months to 1.24 (P = 0.871) and 0.89 (P = 0.568), respectively, at one year.

CONCLUSION

IOL exchange (multifocal to monofocal) to solve neuroadaptation failure in this case series resulted in significant improvements in dysphotopsia and improved distance visual function. However, UNVA worsened and patient satisfaction after exchange remained suboptimal with 77% claiming they would not repeat the lens exchange, suggesting the value of near vision spectacle independence for these patients.

Fifteen years of IOL exchange: indications, outcomes, and complications

PURPOSE

To report the indications, frequency, and outcomes regarding intraocular lens (IOL) exchange in 2 university hospital tertiary referral settings over a period of 15 years.

SETTING

Ophthalmology departments of the University Hospital Antwerp and the University Hospital Leuven, Belgium.

DESIGN

Retrospective cross-sectional study.

METHODS

In this retrospective study, included were patients who underwent an IOL exchange between 2002 and 2017. Patient demographics, surgical indication, comorbidities, visual outcomes, and complications were reported. Patients who underwent IOL repositioning or add-on IOL implantation or extraction, and patients who were left aphakic, were excluded.

RESULTS

Included in the study were 492 eyes. The mean age was 66.0 ± 13.3 years (range 19-91 years). The mean time between primary surgery and IOL exchange was 54.61 ± 67.07 months (range 0-343 months). Primary indication for explantation was IOL opacification, and the most common ophthalmic comorbidity was a previous history of vitreoretinal surgery. Preoperatively, the mean uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA) were 0.47 ± 0.27 (range 0-1) and 0.61 ± 0.32 (range 0-1.2), respectively. Postoperative UCVA and CDVA was 0.7 ± 0.3 (range 0-1.2) and 0.8 ± 0.28 (range 0.05-1.6), respectively. The increase in both CDVA and UCVA was statistically significant (P < .001, paired t test). The most common complication perioperatively was vitreous prolapse, which occurred in 61 eyes (16%).

CONCLUSIONS

IOL exchange is a challenging yet valuable treatment option for a wide spectrum of problematic IOL outcomes. The most common indication remains IOL opacification, although IOL dislocation and patient dissatisfaction are increasing as indications.

Intraocular lens explantation in Spain: indications and outcomes at a tertiary referral center from 2010 to 2018

PURPOSE

To evaluate the causes of IOL explantation, techniques for secondary IOL implantation, visual outcomes and complications.

METHODS

Setting: Department of Ophthalmology Complexo Hospitalario Universitario A Coruña, Spain.

DESIGN

Retrospective study. All explanted IOLs from January 2010 to June 2018 were included. Medical records were reviewed to determine the surgical indication for IOL explantation, type of IOL implanted, time between surgeries, visual outcomes and surgical complications.

RESULTS

One hundred forty-one IOLs were explanted (134 patients). Mean time from original surgery to IOL explantation was 7.89 ± 5.81 years. Causes of IOL explantation were IOL dislocation (81.56%)-in-the-bag IOL dislocation (71.63%), out-of-the-bag IOL dislocation (9.9%)-corneal decompensation (12.05%), refractive surprise (3.5%), uveitis-glaucoma-hyphema syndrome (1.4%), IOL opacification (1.4%). Procedures for secondary IOL implantation were retropupillar iris-claw IOL (63.8%), flanged scleral fixated IOL (9.2%), three-piece IOL in ciliary sulcus (8.5%), angle-supported anterior chamber IOL (7.1%), in-the-bag IOL (3.5%), scleral fixated IOL with sutures (0.7%). Ten cases (7.1%) were left aphakic. Mean preoperative and postoperative logMAR CDVA were 1.34 ± 0.87 and 0.63 ± 0.69, respectively (p = 0.000). Mean preoperative IOP and postoperative IOP were 16.78 ± 4.49 and 15.53 ± 3.476 mmHg, respectively (p = 0.005). Complications include cystoid macular edema (7.8%), glaucoma (7.1%), IOL luxation (2.1%), retinal detachment (1.4%), trophic ulcer and leucoma (1.4%), corneal decompensation (1.4%).

CONCLUSIONS

In-the-bag IOL dislocation was the most frequent indication for IOL explantation, followed by pseudophakic bullous keratopathy. Simultaneous IOL exchange for a retropupillar iris-claw IOL was the most frequent procedure for secondary IOL implantation. Mean CDVA improved significantly and IOP decreased significantly after IOL explantation. The most frequent postoperative complication was cystoid macular edema.

Indications and Outcomes for the Removal of Intraocular Lens Implants in a Retinal Surgery Practice

BACKGROUND AND OBJECTIVE

To describe the reasons for and clinical outcomes of intraocular lens (IOL) removal, with or without exchange, in the setting of retina surgery.

PATIENTS AND METHODS

This is a retrospective, noncomparative, consecutive, interventional case series of patients undergoing IOL removal at an academic referral center performed by a single surgeon between 2002 and 2013. Data collected included baseline patient characteristics, visual acuity (VA), type of IOL, reason for IOL removal, and postoperative complications.

RESULTS

The study cohort included 63 eyes with IOL removal. Of these, 51 (81%) were left aphakic. For cases of IOL opacification or dislocated IOL (56), the decision to remove was made for 35 (63%) during concurrent retinal surgery due to obstruction in visualization. Overall, the most common reason for removal of the IOL was IOL opacities in 42 eyes (67%), followed by nonspecific nature of opacities (n = 19; 45%), oil artifact (n = 17; 40%), opaque nonvascular membranes (n = 4; 10%), and fibrovascular proliferation (n = 2; 5%). Other causes for removal were IOL dislocation (n = 14; 22%), endophthalmitis (n = 7; 11%), and broken IOL haptic (n = 1; 2%). The composition of the 42 IOLs with opacification included 19 (45%) silicone, 14 (33%) unspecified, five (12%) polymethyl methacrylate, and four acrylic (10%). From the 17 IOLs removed due to oil opacification, 15 (83%) were silicone, and two (17%) were unspecified. Postoperative complications included recurrent retinal detachment (n = 13; 21%), hypotony (n = 8; 13%), phthisis bulbi (n = 8; 13%), corneal edema (n = 7; 11%), cystoid macular edema (n = 5; 8%), elevated intraocular pressure (n = 3; 5%), vitreous hemorrhage (n = 3; 5%), hyphema (1; 2%), anterior synechiae (1; 2%), and subretinal hemorrhage (1; 2%) The mean (SD) immediate, 3 months, and final best-corrected VA in logMAR were 2.18 (0.47), 1.85 (0.82), and 1.97 (0.85).

CONCLUSION

The vitreoretinal surgeon must be prepared for IOL removal, especially if IOL opacification and dislocation compromise the view or capability to achieve primary retinal reattachment objectives. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:504-508.].

A Survey of Intraocular Lens Explantation: A Retrospective Analysis of 23 IOLs Explanted during 2005

Purpose

To evaluate the indications, lens styles, perioperative findings, and results of intraocular lens (IOL) explantation or exchange performed in the authors department in 2005.

Methods

The retrospective analysis comprised 22 patients (23 eyes). Twenty-one eyes had previous phacoemulsification and IOL implantation, one eye secondary aphakic IOL, and one eye phakic IOL implantation. The indications for IOL explantation/exchange and perioperative complications were evaluated. The best-corrected visual acuity (BCVA) before and after surgery was compared.

Results

Time from initial surgery to explantation/exchange varied from 1 to 121 months, median value was 46 months. The IOLs were explanted using local anesthesia and in 21 eyes replaced with new lens. Indications for IOL removal were opacification of the IOL in 12 eyes, malposition of the IOL in 5 eyes, postoperative refractive error in 2 eyes, recurrent toxic anterior segment syndrome in 1 eye, pseudophakic dysphotopsia in 1 eye, endothelial cell loss in phakic anterior chamber IOL in 1 eye, and visual discomfort with intraocular telescopic lens in 1 eye. The mean BCVA (decimal scale) before and after IOL explantation/exchange was 0.562±0.279 and 0.627±0.276, respectively. There was no significant difference in visual acuity before and after IOL exchange (Wilcoxon test).

Conclusions

The most frequent indications for IOL explantation/exchange were opacification of the IOL and IOL malposition. Surgeries were uneventful in most cases. Final visual results have been largely good. Long-term follow-up of patients with various types of IOLs should be maintained.

Glued trans-scleral intraocular lens exchange for anterior chamber lenses in complicated eyes: analysis of indications and results

PURPOSE

To determine the clinical outcomes after glued trans-scleral posterior chamber intraocular lens (IOL) exchange for anterior chamber (AC) IOL.

DESIGN

Retrospective case series.

METHODS

Eyes with AC IOL explantation with glued IOL implantation in a single setting at the Dr Agarwal Eye Hospital and Eye Research Centre, Chennai, India, from 2008 through 2012 were included. Data were collected from the patient records.

MAIN OUTCOME MEASURES

Corrected distance visual acuity (CDVA) in logarithm of the minimal angle of resolution units, intraocular pressure, AC reaction, AC depth, central corneal thickness, central macular thickness, endothelial cell density, and endothelial cell loss (percentage) were determined before and after IOL exchange.

RESULTS

Thirty-eight eyes with mean follow-up of 24.1 ± 15.4 months (range, 8 to 60 months) were analyzed. The indications were corneal decompensation (39.4%), malpositioned AC IOL (28.9%), uveitis (15.7%), glaucoma (13.1%), and broken haptic (2.6%). There was significant improvement in the postoperative CDVA (P = .000) and central corneal thickness (P = .000) after AC IOL removal. CDVA better than 20/60 was obtained in 65.7% eyes. Thirty-four (86.8%) eyes showed an increase in the CDVA after IOL exchange. The mean endothelial cell loss was 3.4 ± 2.4% (range, 0.13% to 10.5%). There was significant correlation between the CDVA and the central corneal thickness (P = .000). There was significant change in the AC depth (P = .000), the intraocular pressure (P = .005), and the AC inflammation (P = .000) after IOL exchange. The preoperative macular edema in 3 eyes resolved after surgery (mean central macular thickness, 205.6 ± 7.2 μm).

CONCLUSIONS

Glued trans-scleral fixated posterior chamber IOL exchange for AC IOL can be an excellent alternative in eyes with ocular complications related to AC IOL.

[Iritis with destabilization of the intraocular pressure due to dislocation of a posterior chamber intraocular lens]

This report concerns the case of a 67-year-old male patient who underwent uncomplicated phacoemulsification with implantation of a posterior chamber intraocular lens (IOL). After an interval of 2 months the patient developed iritis together with an uncontrollable increase in intraocular pressure. After a detailed examination a dislocated haptic of the IOL was identified as the cause of the symptoms. The dislocation had led to uveitis-glaucoma-hyphema syndrome although no hemorrhage was observed. In addition to this complication the haptic had arroded the zonular complex which made implantation of an anterior chamber lens necessary. Although improvements in operating techniques, lens materials and designs have been made uveitis-glaucoma-hyphema syndrome has to be kept in mind. Surgical intervention is the only therapeutic option.

Techniques of intraocular lens suspension in the absence of capsular/zonular support

Implantation of intraocular lenses has become the standard of care in the aphakic state. Ideally, the lens is placed in the capsular bag, which affords stable fixation at a position closest to the nodal point of the eye. However, there will always be instances where this will not be possible. Congenital weakness of the lens zonules in various conditions, trauma, and surgical complications of cataract surgery are just some examples. In this article, we review the methods that have been devised to allow intraocular lens implantation in the absence of capsular or zonular support. These include anterior chamber angle and iris-fixated lenses, as well as posterior chamber iris- and scleral-sutured lenses. The various lenses are described, and the techniques involved, advantages and disadvantages, complications, and results of each method are discussed. It is hoped that this article will provide a comprehensive overview of ways to deal with a problem that can still result in a very good visual outcome for the patient. This is particularly relevant given the many recent developments and refinements of methods in implanting intraocular lenses.

Management of a posteriorly dislocated endocapsular tension ring and a foldable acrylic intraocular lens

We report a rare case of late spontaneous extension of a posterior capsule tear from lateral traction of an endocapsular ring, resulting in dislocation of the capsular tension ring and acrylic intraocular lens (IOL) into the vitreous cavity. A 3-port pars plana vitrectomy was performed to explant the prostheses; the eye was made pseudophakic by placement of a scleral-fixated posterior chamber IOL. The combined triple procedure was safe and effective.

Complications and clinical outcomes of intraocular lens exchange in patients with calcified hydrogel lenses

PURPOSE

To evaluate the outcomes of intraocular lens (IOL) exchange in patients with calcified hydrogel IOLs.

SETTING

Ophthalmology departments of 2 university hospitals in Hong Kong, China.

METHODS

Fifteen patients developed loss of vision resulting from calcification of hydrogel IOLs. The calcified IOLs were explanted and replaced with new IOLs. The best corrected visual acuity before and after surgery was measured and compared.

RESULTS

The mean visual acuity was 0.03 (range 0.01 to 0.20) before IOL exchange and 0.20 (range 0.01 to 0.50) 3 months after; the difference was significant (P <.001). Acuity improved approximately 5 Snellen lines. Complications included posterior capsule rupture in 2 patients and zonular dehiscence in 3 patients; the secondary IOL was placed in the anterior chamber or ciliary sulcus in these patients. Three patients required cutting of the haptics before the calcified IOL could be removed.

CONCLUSION

Intraocular lens exchange was an effective treatment in patients with calcified hydrogel IOLs.

Cytopathology of explanted intraocular lenses and the clinical correlation

PURPOSE

To study the cytopathological features of explanted intraocular lenses (IOLs) and correlate the features with their clinical presentation.

SETTING

Ocular Pathology Department, Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India.

METHODS

The study comprised 61 explanted IOLs (48 posterior chamber IOLs and 13 anterior chamber IOLs) removed for the following reasons: pseudophakic bullous keratopathy (36), recalcitrant uveitis (7), retinal detachment (10), endophthalmitis (5), uveitis (7), IOL subluxation (2), and painful blind eye (1). The IOLs were stained with hematoxylin and eosin using a simple cytological technique. The cytopathological features were studied and correlated with the clinical presentations.

RESULTS

The mean time of IOL explantation was 10.1 months after surgery. Twenty-one IOLs had granulomatous and nongranulomatous inflammations and 4, nongranulomatous inflammations. One IOL had fungal filaments on the surface.

CONCLUSIONS

Intraocular lenses can produce both granulomatous and nongranulomatous inflammation. Granulomatous inflammation was the most common in this series. The surface of IOLs explanted because of intraocular infection may show infective agents.

[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.

Hypopyon uveitis

Hypopyon uveitis has inflammatory, infective, and neoplastic causes and a high association with systemic disease. Careful questioning of the patient and detailed examination of the eye for other signs is necessary to guide the differential diagnosis and relevant investigations. Because the underlying causes require very different types of investigation and, if missed, can have serious sequelae for the patient, a rational approach based on the understanding of the causes of hypopyon uveitis is imperative. In this review, hypopyon uveitis is considered in the context of the associated ocular and systemic diseases that cause it.

Vitrectomy to remove a posteriorly dislocated endocapsular tension ring

We treated a patient who had a posteriorly dislocated endocapsular ring associated with decreased vision and intravitreal cortical remnants. The ring was removed by uneventful pars plana vitrectomy. By the last examination, best corrected visual acuity had improved to 6/12 and intraocular pressure had stabilized to within normal limits. A posteriorly dislocated endocapsular ring is a rare complication of cataract surgery. Its removal by pars plana vitrectomy under direct observation is effective and safe.

Lens implant selection with absence of capsular support

If contact lens or spectacle correction is not viable, little debate exists that the secondary placement of an intra-ocular lens (IOL) is the method of choice in the absence of capsular support. The choice of IOL mainly depends on the preoperative status of the eye (eg, aphakia in children) and the selected location for the implant. Theoretically, there are several IOL implantation approaches in cases without capsular support: an angle-supported anterior chamber (AC) IOL, an iris-fixated ACIOL, an iris-sutured or iris-fixated posterior chamber (PC) IOL and a transsclerally sutured PCIOL. No consensus exists, however, on the indications as well as on the relative safety and efficacy of these different options. Implantation of modern ACIOLs, like the refined open-loop or iris-fixated claw (toric) ACIOLs, have regained popularity and provide a valuable alternative to sutured PCIOLs. However, in the absence of capsular support, the transsclerally sutured PCIOLs offer numerous advantages for certain eyes. Because of its anatomic location, the sutured PCIOL is more appropriate for eyes with compromised cornea, peripheral anterior synechiae, shallow anterior chamber, or glaucoma. Moreover, sutured PCIOLs are appropriate if the patient with aphakia is young or has a life expectancy of 10 years or more. Recent technological advances, including PCIOL with iris diaphragm for aniridia, toric ACIOLs, and small-incision surgery with foldable, transsclerally sutured IOLs, seem to further improve clinical outcomes.

Explantation of intraocular lenses

Cataract surgery has evolved recently along with the development of intraocular lenses. With this evolution of intraocular lenses from anterior chamber and iris-fixated lenses to more modern foldable posterior intraocular lenses has come an evolution in the complications that necessitate removal of the intraocular lens. Early generations of anterior chamber and iris-fixated intraocular lenses often had severe complications associated with them, such as pseudophakic bullous keratopathy, uveitis-glaucoma-hyphema syndrome, and chronic cystoid macular edema. With modern foldable intraocular lenses, decentration-dislocation and incorrect lens power, and glare and optical aberrations are leading indications for explantation. Some complications appear to be unique to particular styles of modern intraocular lenses, with incidence of glare and optical aberrations increasing, especially in acrylic and multifocal intraocular lenses. The clinical outcomes after an intraocular lens explantation or exchange have also improved markedly with the advent of modern foldable intraocular lenses. Postoperative visual acuity results are dependent on the preoperative complications associated with the explanted intraocular lens. Final visual results after exchange of modern foldable intraocular lenses have been uniformly good. This is probably because of fewer severe complications that lead to explantation of the intraocular lens.

Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part I: Elimination of fixation-induced decentration to achieve precise optical correction and visual rehabilitation

PURPOSE

Realizing that precise posterior chamber intraocular lens (PC-IOL) centration is needed to consistently achieve good optical results and visual rehabilitation after modern cataract surgery, the authors assessed the status and success rate of lens haptic fixation and its correlation with lens optic centration-decentration in a large series of eyes with PC-IOLs obtained postmortem.

DESIGN

Prospective analysis of pseudophakic eyes obtained postmortem.

PARTICIPANTS

A total of 3493 human eyes obtained postmortem, the largest database of such specimens available to date.

METHODS

Miyake-Apple posterior photographic technique.

MAIN OUTCOME MEASURES

The amount of decentration of rigid PC-IOLs and small-incision foldable PC-IOLs was analyzed, and the results were correlated with the type of fixation that had been achieved in each case.

RESULTS

Determination of mean values revealed that capsular bag fixation was achieved in 52.05% of eyes, asymmetric bag-sulcus fixation in 34.21 % of eyes, and sulcus-sulcus fixation in 13.74% of eyes. Asymmetrically fixed lenses consistently showed significant decentration. During the past 5 years (1993-98), the overall rate of in-the-bag fixation increased to 59.2%; by 1998 it had increased to 64%. Most significantly, success in achieving bag-bag fixation of foldable IOLs implanted in association with modern capsular surgery with small incisions has surged to 90% over the past 4 years.

CONCLUSIONS

The authors found a direct correlation of decentration in eyes with asymmetric fixation, and the results underscore the need for careful in-the-bag haptic placement. Although few surgeons today would dispute the goal to implanting haptics in the capsular bag, these findings show that the overall success rate over the years has, while improving, remained surprisingly low. The overall success rate of about 60% seen with all lens designs is probably as good as can be expected with classic large-incision extracapsular techniques. However, and most important and encouraging, the success rate of haptic fixation in cases with foldable lenses has improved dramatically during the past 4 years (up to the 90% range). This coincides with the present emphasis on modern capsular surgery and small-incision techniques used to insert these lenses.

Intraocular lens complications requiring removal or exchange

Intraocular lens (IOL)-related complications are caused primarily by mechanical trauma, inflammatory or infectious complications, or optical problems. Complications may occur at the time of surgery or be the result of an ongoing postoperative process. Mechanical and inflammatory injury may produce corneal decompensation, cystoid macular edema, hyphema, uveitis, and glaucoma, causing reduced vision and in some cases chronic pain. Optical problems may be due to a wrong power of the IOL or to postoperative decentration or dislocation of the lens. Ophthalmologists should be aware of the indications for IOL removal or exchange in those patients who have ongoing IOL-induced injury or impairment. Removal or exchange of an IOL frequently involves a complex decision-making process and is often associated with immense technical challenge. Various medical and surgical treatments may be tried to correct IOL problems before the decision is made to remove or exchange the lens.

Causes of severe decentration and subluxation of intraocular lenses

BACKGROUND

Severe decentration and subluxation of intraocular lenses (IOLs) may lead to double vision, glare and deterioration of vision to the point of functional aphakia. The purpose of the present study was to analyse causes for severe IOL dislocation.

MATERIAL AND METHODS

Between January 1989 and January 1996, 37 patients required IOL exchange because of decentrated or subluxated posterior chamber lenses. Twenty-five of the exchanged lenses were implanted in our hospital, 12 lenses elsewhere. After explantation the lenses were examined by light and electron microscopy.

RESULTS

In 10 eyes, asymmetric implantation of the posterior chamber lens was responsible for decentration. Three of the lenser concerned were multifocal IOLs. Asymmetric implantation led to a significantly higher rate of explantations in eyes with multifocal lenses (P < 0.005). In five eyes decentration developed due to asymmetric capsular shrinkage, in four eyes due to posterior synechiae. A lens subluxation developed in three eyes as a result of rupture of the posterior capsule and in nine eyes because of zonular defects. In three cases decentrations were induced by an extensive secondary cataract. Macroscopically visible changed geometry of the haptics was found in nine lenses; eight of these had polypropylene haptics. Seven lenses showed severely altered haptics on electron-microscopic examination. In four eyes subluxated lenses had to be explanted together with the capsular bag because of severe defects of the zonula, which caused decentration in nine eyes.

CONCLUSIONS

Asymmetric implantation of posterior chamber lenses should be strictly avoided. Multifocal lenses require special attention concerning symmetric capsulorhexis and positioning of their haptics.

Glaucoma associated with uveitis

Raised intraocular pressure is a common and frequently serious complication of anterior uveitis. The milieu of inflammatory cells, the mediators they release, and the corticosteroid therapy used to treat the uveitis can participate in the pathogenesis of uveitic glaucoma. These factors alter the normal anatomic structure of the anterior chamber and angle, influencing aqueous production and outflow. These changes act to disrupt the homeostatic mechanisms of intraocular pressure control. Structural changes in the angle can be acute, such as in secondary angle closure with pupillary block glaucoma, or chronic, such as combined steroid-induced and secondary open angle glaucoma. Management of uveitic glaucoma may be difficult because of the numerous mechanisms involved in its pathogenesis. Diagnostic and therapeutic decisions are guided by careful delineation of the pathophysiology of each individual case. The goal of treatment is to minimize permanent structural alteration of aqueous outflow and to prevent damage to the optic nerve head. This article reviews the pathogenesis of uveitic glaucoma, with specific attention to etiology. Medical and surgical therapies are also discussed, with emphasis on the more recent developments in each category.

Intraocular lens implants: a biocompatibility review

The natural aging process of the eye inevitably leads to the formation of a cataract, resulting in an increasing loss of vision. A cataract is the clouding of the natural lens in the eye and represents a major physical impairment. Modern surgical techniques allow for removal of the clouded lens and replacement with a prosthetic intraocular lens. This article reviews the intraocular tissue response to the implant, which frequently leads to postoperative complications for the patient.

Centration and fixation of silicone intraocular lenses: clinicopathological findings in human autopsy eyes

PURPOSE

To analyze centration and fixation of three-piece and one-piece silicone intraocular lenses (IOLs) in human autopsy eyes.

SETTING

Center for Intraocular Lens Research, Medical University of South Carolina, Charleston.

METHODS

Thirty eyes among those submitted to the center between 1986 and 1994 were evaluated. The globes were sectioned at the equatorial plane and photographed from a posterior view. Gross examination was performed to determine IOL type, fixation, centration, and additional pathology. The results were compared with those of a control group of autopsy eyes implanted with one-piece and three-piece poly(methyl methacrylate) (PMMA) IOLs. The control group matched the silicone group in patient age, fixation site, and duration of implantation.

RESULTS

Twenty-three eyes (79.3%) had three-piece silicone IOLs and 7 eyes (20.7%), one-piece plate IOLs. Average patient age in the three-piece group was 77.3 years +/- 6.7 (SD) and in the one-piece group, 74.3 +/- 3.8 years. The 30 IOLs were symmetrically fixated in the bag. Average decentration of the three-piece and one-piece IOLs did not differ significantly, 0.37 +/- 0.31 mm and 0.26 +/- 0.13 mm, respectively (P = .37). There was also no significant difference in decentration between the silicone groups and the PMMA groups (P = .93).

CONCLUSION

Centration and fixation of silicone IOLs were equivalent to those of standard PMMA IOLs.

Analysis of 100 explanted one-piece and three-piece silicone intraocular lenses

PURPOSE

The authors analyzed incidence and types of complications seen after implantation of silicone posterior chamber intraocular lenses (PC IOLs). These data were compared with those obtained in previous studies with standard polymethylmethacrylate IOLs.

METHODS

Data from the laboratory database were collected on 100 explanted silicone IOLs submitted to the Center for Intraocular Lens Research from 1986 to 1994.

RESULTS

Of the 100 IOLs, 63 were three-piece designs with polypropylene loops and 37 were one-piece plate lenses. The two most important reasons for explantation were IOL decentration (42.0%) and inflammation (27.7%). There was no significant difference for the reasons of explantations between one- and three piece IOLs (P > 0.1). Intraocular lenses that had been removed due to inflammatory reactions had a significantly longer implant duration (19.2 +/- 18.9 months) than lenses that were explanted because of decentration (9.19 +/- 12.1 months) (P = 0.018).

CONCLUSIONS

The results presented here showed that there is no substantial difference between these IOLs and polymethylmethacrylate lenses in terms of reasons for explantation. The authors' data suggest that clinical outcome is not as dependent on the type of lens selected as it is on the quality of surgery. The key to good results is the use of "capsular surgery," namely techniques that ensure secure in-the-bag IOL fixation.

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.

The role of intraocular lens exchange in the management of major implant-related complications

This study evaluates the role of intraocular lens exchange procedures in the management of major implant-related complications. Medical records of 30 patients undergoing intraocular lens exchange at the Leeds General Infirmary from 1 January 1984 to 30 November 1991 were reviewed. Details of their primary implantation surgery, intervening ophthalmic history, lens exchange surgery and outcome were analysed. Follow-up ranged from 3 to 210 weeks. Seventy-six per cent of cases achieved final visual acuity of 6/12 or better. Visual acuity improved in 60%, worsened in 6.6% and was unchanged in 33.4% compared with pre-operative levels. Three patients had cystoid macular oedema, 3 ocular hypertension, 2 bullous keratopathy, 1 chronic anterior uveitis and 1 patient developed a retinal detachment. This approach to managing major implant-related complications gives good visual results. There is a significant complication rate but the risk-benefit ratio justifies the use of the technique.

Explantation of posterior chamber lenses

A consecutive series of 119 explanted posterior chamber lenses is reviewed. Seventy (58.8%) were removed because of dislocation or improper fixation, 15 (12.6%) because of anisometropia, and 18 (15.1%) because of chronic inflammation. Sixty-two (52.1%) of these explantations probably occurred for reasons that can be avoided by changes in preoperative, operative, or postoperative techniques. The rate of posterior chamber lens explantations is quite low considering the large number of lenses implanted; with changing surgical techniques, we anticipate that the number of lenses requiring removal will decrease.