Scanning electron microscopy of removed intraocular lenses

Current Concepts of the Uveitis-Glaucoma-Hyphema (UGH) Syndrome

PURPOSE

To discuss the pathophysiology, etiology, and current management strategies of uveitis-glaucoma-hyphema (UGH) syndrome.

METHODS

Literature review.

RESULTS

The classic UGH syndrome associated with anterior chamber intraocular lenses (ACIOL) have decreased in incidence with the modernization of IOL design and surgical techniques. The current UGH syndrome is increasing in prevalence largely related to a parallel increase in late onset dislocations of intraocular lenses (IOLs) and the developing techniques to remedy that condition. The modern features of UGH can present as cystoid macular edema, intraocular pressure elevation typically not attributed to UGH, and recurrent vitreous hemorrhage, unlike the original description as described by Ellingson in 1978. Medical management to control inflammation, reduce intraocular pressure, and reduced the bleeding diathesis are mainstays of therapy. However, surgery with IOL repositioning or exchange should be reserved for cases that are refractory to or progressing despite medical treatment.

CONCLUSIONS

UGH syndrome is an increasingly common, poorly understood, and often subtle, manifestation of an anatomic disturbance post intraocular surgery that persists with continued evolution of intraocular surgical techniques and new imaging modalities to aid in its diagnosis.

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.

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.

Cellular invasion on the surface of intraocular lenses. In vivo cytological observations following lens implantation

Cellular growth on intraocular lenses can be observed by using a specular microscope. We examined in vivo the cellular pattern on the surface of implanted lenses during the early postoperative period in 63 patients. In every case inflammatory cells were noted on the lens surface at some point during the observation period. These often showed a spindle-like appearance resembling fibroblasts. The density of the cell population increased during the following days but usually did not exceed 100 cells/mm2. From the end of the first week, multinucleated giant cells may appear. In one case, a patient with a severe postoperative iritis and hypopyon demonstrated an extremely pronounced and long-lasting cellular proliferation.

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.

Intraocular lenses: a histopathologic study of eyes, ocular tissues, and intraocular lenses obtained surgically

Eyes, ocular tissues, and intraocular lenses obtained surgically from 179 eyes of 177 patients were studied to determine the histopathologic features of complications related to anterior chamber, iris-fixation, iridocapsular, and posterior chamber lens implantation.

Morphology of pseudophakic precipitates on intraocular lenses removed from human patients

Cellular precipitates on the surface of 52 intraocular lenses removed from human patients for various reasons from one week to five years following implantation were studied with cytologic techniques and scanning electron microscopy. A variety of cellular responses were characterized: mononuclear precipitates composed of lymphocytes and macrophages, multinucleated giant cells, and a fibroblastic proliferation. Polymorphonuclear leukocytes were encountered less frequently. Acellular membranous precipitates were also observed. Cellular response was related to clinical history to correlate temporal and possible etiopathogenic factors in the formulation of these precipitates and their possible relationship to implant failure.

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.

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.

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.