Pathological and scanning electron microscopic evaluation of the 91Z intraocular lens

Irregularities on the surface of single-piece AcrySof SA60AT intraocular lenses

PURPOSE

To report a case series of what initially appeared to be macroscopic biomaterial deposits and irregularities on the surface of AcrySof SA60AT intraocular lenses (IOLs) (Alcon Inc.)

SETTING

Department of Ophthalmology and Somerset Hospital, Taunton, United Kingdom; Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, Salt Lake City, Utah, USA; and Intraocular Implant Unit, Sydney Eye Hospital, University of Sydney, Sydney, Australia.

METHODS

Twelve AcrySof SA60AT IOLs were initially thought to have irregularities on their surfaces when examined under the operating microscope before implantation in the capsular bag during cataract surgery. The IOLs were sent for further analysis, including gross examination and light and scanning electron microscopy, to John A. Moran Eye Center, Salt Lake City, Utah, USA, and to Alcon Laboratories, Hemel Hempstead, United Kingdom.

RESULTS

Light microscopy revealed the presence of irregular fine lesions on the IOLs' optics and haptics. The lesions consisted of elevations and depressions of the IOL surface that were present on both the anterior and the posterior surfaces of the IOLs. Scanning electron microscopy confirmed the presence of physical/mechanical damage to the IOLs, which was thought to originate from the packaging. The manufacturer believed this to have resulted from compression of the IOL between the container and its cover.

CONCLUSIONS

Implantation of an imperfect IOL remains a potentially serious occurrence. Faults still occur in modern IOLs, and some defects can be detected by examining the IOL under the operating microscope before implantation into the eye.

Cataract treatment in the beginning of the 21st century

PURPOSE

To describe the principles upon which present day cataract treatment success resides.

DESIGN

Literature review and collective experience of the authors.

RESULTS

Surgical removal remains the standard treatment for cataract now and in the foreseeable future. Ultrasound cataract removal with a foldable "in-the-bag" intraocular lens with a truncated edge treated for dysphotopsia best correlates with core treatment principles, as we now understand them. Improving refractive results is an important trend. The worldwide burden of this problem is immense.

CONCLUSIONS

While results for treatment of cataracts are excellent today, improvements in safety and refraction precision are needed. Other approaches are desperately needed to stem the worldwide tide of cataract related ocular dysfunction.

Scanning electron microscopic and histologic evaluation of the AcrySof SA30AL acrylic intraocular lens. Manufacturing quality and morphology in the capsular bag

PURPOSE

To evaluate the properties of the AcrySof(R) SA30AL (Alcon Laboratories, Inc.) single-piece foldable posterior chamber intraocular lens (IOL).

SETTING

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

METHODS

Two nonimplanted clinical-quality AcrySof IOLs were examined by gross, light, and scanning electron microscopy (SEM). In addition, 2 eyes implanted with this IOL obtained post-mortem, the first such eyes accessioned in our laboratory and the first described to date, were examined using the Miyake-Apple posterior photographic technique and by histologic sections.

RESULTS

Scanning electron microscopy of the SA30AL IOL showed excellent surface finish. The edge of the optic was square (truncated) and had a matte (velvet or ground-glass) appearance, a feature that may minimize edge glare and other visual phenomena. A well-fabricated square or truncated optic edge was demonstrated. Miyake-Apple analysis revealed that the SA30AL IOL showed appropriate fit and configuration within the capsular bag. Histologic correlation of the IOL's square edge and its relation to the capsular bag and adjacent Soemmering's ring were noted.

CONCLUSIONS

The AcrySof SA30AL IOL is a well-fabricated lens that situates well in the capsular bag. The truncated optic and its relationship to adjacent structures show a morphological profile that has been shown to be highly efficacious in reducing the rate of posterior capsule opacification.

[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.

Scanning electron microscopic characteristics of small-incision intraocular lenses

PURPOSE

To evaluate the surface characteristics of commonly used, small-incision, intraocular lenses (IOLs).

METHODS

Representative samples of five groups of foldable IOLs (4 silicone and 1 acrylic) underwent surface and edge-finish examination using a slit lamp. The IOLs were folded using a folding block and forceps. All the IOLs then were examined using a scanning electron microscope. A one-piece polymethylmethacrylate IOL was used for comparing surface-finish characteristics. The IOLs were examined for optic surface quality, edge finish, haptic, haptic/optic junction, and possible post-folding modifications.

RESULTS

Slit-lamp evaluation of the surface quality of all of the silicone lenses demonstrated a smooth finish of the optic surface, edge, and haptics. Scanning electron microscopic analysis of the IOLs demonstrated adequately finished haptics or footplates and optics. Excess molding flash was seen on the edges of the some of the silicone IOLs, and no molding flash was observed on others. The acrylic IOL had a somewhat sharper optic edge. Irregular finish of the haptic/optic junctions of some of the IOLs (both silicone and acrylic) was noted.

CONCLUSIONS

Currently available foldable IOLs have demonstrated adequate lens finish. However, irregularities of the haptic/optic junctions and molding flash are present on most IOLs evaluated, indicating room for improvement in the finish of foldable IOLs. Phacoemulsification with capsular bag IOL placement may decrease the clinical significance of these relatively subtle lens finish irregularities.

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.

Posterior capsule opacification

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

Toxic anterior segment inflammation following cataract surgery

Cataract extraction with posterior chamber intraocular lens implantation is rarely complicated by an acute, sterile, anterior segment inflammation. We report three unrelated cases of acute intraocular inflammation following uncomplicated cataract extraction and posterior chamber intraocular lens placement. A constellation of clinical features were found in these cases. The hallmark of this entity was an acute toxic inflammatory reaction occurring in the anterior segment on the first postoperative day. Typically, widespread corneal edema with diffuse corneal endothelial damage occurred, accompanied by a fixed, dilated pupil with significant iris atrophy and sometimes a severe secondary glaucoma. Since all cultures were negative, the resulting inflammatory processes were not a result of endophthalmitis. We believe that a toxic insult introduced into the anterior chamber at the time of surgery precipitated the acute inflammatory processes seen in these cases.

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.

Experimental evaluation of a phakic anterior chamber implant in a primate model. Part II. Pathology

Anterior chamber intraocular lenses were implanted in 50 phakic primate eyes and followed by serial histopathology for two years. Significant observations included corneal endothelial alterations, haptic erosion into and encapsulation by peripheral iris and ciliary body, and chronic low grade inflammation.

Experimental evaluation of a phakic anterior chamber implant in a primate model. Part I. Clinical observations

Anterior chamber intraocular lenses were implanted in phakic cynomolgus monkey eyes and followed clinically over two years. Significant observations included erosion and/or uveal envelopment of the haptic and a decrease in endothelial cell counts. There was good positional stability, no significant inflammation, initial ocular hypotension that returned to normal intraocular pressure, and no evidence of cataracts or cystoid macular edema.

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.

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.

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

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

Visual results of suture-fixated posterior chamber lenses during penetrating keratoplasty

Between August 12, 1982, and June 30, 1987, 233 consecutive eyes had posterior chamber intraocular lenses (PC IOLs) suture-fixated to the posterior aspect of the iris during penetrating keratoplasty (PKP). In all cases, insufficient capsular material was present to provide adequate fixation for the implant. Lenses were placed in 72 aphakic eyes as a secondary implant, and 159 lenses were placed after removal of another implant. Follow-up ranged from 1 year to 68 months with 59.5% of patients achieving visual acuity of 20/40 or better, and 74% of 20/80 or better. Suture-fixating a PC IOL to the iris offers multiple advantages over placement of an anterior chamber lens during PKP. The complication rate appears low, and long-term problems with glaucoma and recurrent corneal decompensation should be reduced.

Sutured retropupillary posterior chamber intraocular lenses for exchange or secondary implantation. The 12th annual Binkhorst lecture, 1988

The histopathologic findings of four eyes obtained postmortem with iris-sutured posterior chamber intraocular lenses (PC IOLs) are described. These IOLs were implanted as exchange procedures. In most instances, the loops were not situated in the ciliary sulcus but rather were suspended behind the iris and ciliary body. Therefore, the primary mechanism of fixation of iris-sutured PC IOLs appears to be the sutures themselves rather than adherence to the ciliary tissues. This report of four eyes is preliminary, but the pathologic analysis, showing few significant lesions attributable to the IOL, provides a reason for optimism for using this technique. A long-term clinical study comparing the results of sutured PC IOLs with those of anterior chamber IOLs (AC IOLs) used in secondary or exchange implantation, as well as collection and analysis of more pathologic specimens, should provide a more definitive answer as to the preferred procedure.

Penetrating keratoplasty for pseudophakic bullous keratopathy associated with semiflexible, closed-loop anterior chamber intraocular lenses

We performed penetrating keratoplasty on 32 eyes that developed pseudophakic bullous keratopathy associated with closed-loop anterior chamber intraocular lenses. All lenses were exchanged at the time of keratoplasty. Seventeen patients received anterior chamber intraocular lenses and 15 patients had a posterior chamber lens sutured to the iris or sclera. Postoperatively, 13 of 32 eyes (41%) achieved a visual acuity of 20/100 or better, and 27 of 32 eyes (84%) had a clear graft. A high incidence of cystoid macular edema (eight cases), and graft rejection (seven cases) resulted in marked visual loss.

Morphological changes and lens position 2 1/2 years after intracapsular cataract extraction with implantation of a semiflexible anterior chamber lens. A prospective re-examination

Morphological changes and lens position were examined in 51 patients 25 to 38 (mean 30) months after intracapsular cataract extraction (ICCE) with implantation of the semiflexible, 3M, style 70, anterior chamber lens. Morphological changes presumably associated with the ICCE proper were: iris transillumination defects (68.6%), rupture of anterior hyaloid membrane (20%), detachment of posterior vitreous (42.9%) and anterior synecchiae (13.7%). The implant-related morphological changes were caused by iris tucking (19.6%), small, mobile lenses causing endothelial disturbance (9.8%), iris-haptic adhesions and progressive ovalling of pupillary form. The present morphological changes were compared with a previously published examination of the same patients performed 4 months after surgery: 9 eyes without tissue changes around the lens feet at the previous follow-up now had iris-haptic adhesions involving from 1 to 4 lens feet. In 8 eyes the iris-haptic adhesions had progressed. Compared with the previous examination the fraction of eyes with tissue changes at the lens feet had risen from 47.1 to 64.7%, while the number of eyes with oval pupils had increased from 54.9 to 80.4%. Contact between lens haptic and iris root seems to constitute a constant stimulus for structural changes of the iris.

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.

In vivo fracture of an extruded polymethylmethacrylate intraocular lens loop

The inferior loop of a semiflexible, closed-loop anterior chamber intraocular lens in the eye of a 72-year-old female fractured at two sites. The loop was composed of extruded polymethylmethacrylate. The inferotemporal portion of the loop was first noted to be broken 25 months postoperatively, and the fractured nasal portion of the same loop was first observed 55 months after implantation. The patient denied any excessive rubbing of the eye or major trauma to the eye or head. Both fractures occurred near the loop-optic junction. The intermittent touch of the cornea by the broken loop caused endothelial damage and edema in the lower one third of the cornea. The two portions of the lens were removed and exchanged with another style of anterior chamber lens. The visual acuity at six weeks postexchange was 20/30.

Anterior chamber lenses. Part I: Complications and pathology and a review of designs

Clinicopathologic data to assist ophthalmologists in choosing a safe and efficacious anterior chamber intraocular lens (IOL) are rapidly becoming available. Two important factors that have led to an increased success rate with some anterior chamber IOL styles are (1) attention to lens design and (2) attention to modern manufacturing and lens finishing techniques. We now know much more about how to achieve appropriate lens flexibility, which decreases the need for perfect sizing. Increased attention has been given to the anterior-posterior vaulting characteristics of IOLs. This has reduced the incidence of various complications such as the intermittent touch syndrome and the uveal chafing syndrome. We recognize several design flaws in some lens styles. For example, there is now a considerable decrease in the number of small-diameter, round-looped anterior chamber IOLs being implanted, particularly those with a closed-loop configuration. Several problems have been and continue to be caused by some poorly manufactured anterior chamber lenses with sharp optic and haptic edges. Technology to assure smooth lens finishing and polishing is available and readily accessible to all manufacturers. Defective lenses should soon be a thing of the past.

Secondary intraocular lens implantation: rigid/semi-rigid versus flexible lenses

Two series of secondary intraocular lens implantations with anterior chamber lenses are reported. Series 1 consisted of our first 199 consecutive procedures using rigid or semi-rigid lenses, performed between May 1, 1977, and September 30, 1982. Series 2 consisted of our first 101 consecutive procedures using flexible lenses, performed between October 1, 1982, and October 30, 1984. Best-corrected final postoperative visual acuity was either better than or within one Snellen line of best-corrected preoperative vision in 84% of cases with rigid or semi-rigid lenses and in 85% of cases with flexible lenses. Surgical complications were minimal in both series. No instances of uveitis-glaucoma-hyphema syndrome were encountered. Endothelial cell loss was low. Because of the short follow-up in Series 2 and the fact that these groups were operated upon at different times, the two series are not directly comparable. Nonetheless, the results do show that secondary intraocular lens implantation is a viable alternative for aphakic patients, particularly those who are intolerant of aphakic spectacles and contact lenses. Certain provisos involving patient education and motivation as well as lens selection are noted in this report.

A survey of intraocular lens explantations

A survey of intraocular lens (IOL) explantations performed during the 1984 calendar year requested dates of implantation and explantation, lens manufacturer, and lens style for anterior chamber, posterior chamber, and iris-supported lenses. The survey was distributed to 3,640 members of the American Society of Cataract and Refractive Surgery and was published in the September 15, 1985, issue of Ocular Surgery News. Information on 1,087 IOL explantations performed during 1984 by approximately 530 surgeons was received. Extrapolation of our survey's responses to the universe of ophthalmic surgeons suggests that the number of IOL explantations ranges from 7,000 to 11,000 each year. The actual numbers and percentages of explantations as well as reported complications vary with the relative percentage of any given manufacturer's lenses implanted and with the popularity of lens styles during the preceding years of implantation. For these reasons, the individual performance of various lenses should be read in the context of this report, considering the time of implantation and the practices that were then in vogue. This survey provides a general picture of IOL explantation but, more importantly, it provides a better structure for a report on 1985 explantations, which will follow.

Additional long-term follow-up on the IOLAB Azar 91Z anterior chamber intraocular lens

A retrospective study of 98 91Z anterior chamber intraocular lenses used with intracapsular cataract extraction was performed. Minimum follow-up was 12 months and average follow-up was two years seven months. These patients were part of a group of 113 91Z patients previously reported with minimum six-months follow-up and an average of one year follow-up. Comparing the two groups showed the number of patients with 20/40 visual acuity declined from 84.1% to 67.4% and those with visual acuity less than 20/400 increased from 0.9% to 5.1%. The number of 91Zs explanted more than doubled from five (4.4%) to 11 (11.2%). Pseudophakic bullous keratopathy not present in the one-year follow-up group is occurring with longer follow-up. This study demonstrates an increasing incidence of inflammatory - hemorrhagic and corneal complications in 91Z patients.

An analysis of semiflexible, closed-loop anterior chamber intraocular lenses

We present the pathologic and scanning electron microscopic findings from 44 semiflexible, all polymethylmethacrylate, anterior chamber intraocular lenses (IOLs). These IOLs, which have round, small diameter, closed loops were removed following a variety of complications, including uveitis and/or the uveitis-glaucoma-hyphema syndrome, secondary glaucoma, pseudophakic bullous keratopathy, cystoid macular edema, erosion into uveal tissue (with and without oval pupil), and iris neovascularization. Over 200,000 of these lens styles have been implanted. Even though the number of these IOLs accessioned in our laboratory is small, we feel this analysis documents some of the problems that may be encountered with this IOL design. Many of the complications documented in our series resulted in severe visual loss. In addition to tissue damage that appeared secondary to the mechanical tissue-to-implant interface, other causes of complications included variations in surgical technique, implantation into eyes with preexisting disease (including eyes that had undergone previous surgery), and damage to tissue that occurred during IOL removal.

Histopathologic correlative study of Kelman-style flexible anterior chamber intraocular lenses

Three of 16 eyes in which Kelman flexible anterior chamber lenses were implanted were obtained for postmortem examination, and the lenses and globes were analyzed histopathologically. Thirteen additional lenses, removed surgically secondary to various complications, were studied by scanning electron microscopy. All of the lenses ere well finished and none showed evidence of degradation or cracking of the polymethylmethacrylate optics or foot plates. Some of the lenses showed deposition of inflammatory debris or erythrocytes, reflecting a clinical history of uveitis. In some cases, the problems seemed to be related to variations in surgical technique or improper sizing.

Broken semiflexible intraocular lens implant

The haptic of a semiflexible anterior chamber intraocular lens (Kelman Quadraflex) broke inside the eye of a 70-year-old man. No history of major eye or head trauma could be elicited from the patient. Clinical manifestations included inferior corneal edema progressing toward the optical axis resulting from a free-floating haptic segment of the lens implant inside the anterior chamber. A significant decrease in endothelial density was documented over a short period of time. The surgical management of this case included removal of the free-floating haptic segment, removal of the lens implant, penetrating keratoplasty, and vitrectomy. Final visual acuity was 20/70.

Complications of intraocular lenses. A historical and histopathological review

Recent improvements in intraocular lens (IOL) design, manufacturing techniques, and surgical techniques have greatly reduced the incidence of complications following implantation, and many authors now consider IOL implantation to be among the most safe and effective major surgical procedures. However, adverse reactions are still seen--some as late sequelae of earlier IOL designs and implantation techniques and some as sequelae of more recent implantations using "state-of-the-art" lenses and surgical techniques. Complications may be due to various factors, including surgical technique, IOL design, or the inability of some eyes with preexisting disease to tolerate an implant. The authors trace the evolution of IOLs since Ridley's first implant, summarizing the modifications in lenses and surgical techniques that were made as complications were recognized. They then review the clinical and histopathological features of selected cases from more than 200 IOLs and/or globes removed due to IOL-related complications and studied in the University of Utah Ocular Pathology Laboratory. It is hoped that this review will provide insights into the pathogenesis of IOL complications, enhancing the current success of implant procedures and stimulating further basic and clinical research in this area.

A comparative study of the 91Z and other anterior chamber intraocular lenses

A retrospective study of 113 91Z anterior chamber intraocular lenses (IOLs) used with intracapsular cataract extraction (ICCE) was performed. The study compared operative complications, visual acuity at three and six or more months, and complications of the 91Z with other types of anterior chamber IOLs. The 91Z had a low incidence of operative complications, good short-term visual acuities, and few short-term complications. It had a high incidence of late, severe, inflammatory/hemorrhagic complications including uveitis-glaucoma-hyphema plus vitreous hemorrhage (UGH+ syndrome), cystoid macular edema, and iris chafing/bleeding. These complications necessitated removal of five lenses (4.5%). An additional 16 patients (14.2%) are under treatment for these late complications. This IOL was often difficult to remove without traumatizing the eye. I have not experienced these late complications with the other types of anterior chamber IOLs reported here; their long-term visual acuities were good and they were stable. None of them has been explanted.

Complications while removing the IOLAB 91Z lens for the UGH-UGH+ syndrome

Five patients having UGH+ syndrome (uveitis-glaucoma-hyphema plus vitreous hemorrhage) with the IOLAB 91Z intraocular lens (IOL) requiring removal are reported. Preoperative gonioscopy showed the polypropylene loops to be enmeshed in synechias. In four cases the IOL was difficult to remove and two cases had significant intraoperative complications. In one case we used the Nd:YAG laser to cut the synechias preoperatively and effected an easy removal.