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Pathological Analysis of a Pannu Universal IOL Authors: Liliana Werner, MD, PhD,1,2 Susan Strenk, PhD,3 Lawrence Strenk, PhD,3 Don Davis, MD,1 Oliver Yeh,1 Nick Mamalis, MD1 From the: 1) Moran Eye Center, University of Utah, Salt Lake City, UT 2) Berlin Eye Research Institute, Berlin, Germany 3) MRI Research, Inc., Cleveland, OH -Design details of the MRI used are proprietary to MRI Research Inc. The other authors have no financial or proprietary interest in any product mentioned in this poster. -Supported in part by a Seed Grant of the University of Utah to Liliana Werner, MD, PhD, and by grants from Alcon Laboratories, and the National Eye Institute (# R43EY018518) to Susan and Lawrence Strenk. In the early 1980s, lenses of a style referred to as “Universal” were designed to be fixated in either, the anterior or the posterior chamber. One of such lenses was invented by J.S. Pannu (Figure 1).1 The flexible loops would allow for implantation in eyes of different sizes. The rings at the extremities of the loops could be used for suturing techniques for fixation of the lens in the ciliary sulcus or in the anterior chamber.2-3 Figure 1: Figure from the Pannu IOL patent 4,435,855, showing the different sites for fixation. We had the opportunity to receive in our laboratory a human eye obtained postmortem, implanted with a Pannu IOL. The aim of our study was to provide clinicians with the pathological features of this specimen. To the best of our knowledge, this is the only report available on long-term effects of this lens in the human eye. Patient: 82-year-old Caucasian man, deceased in 2007. Lens implanted: Single-piece, open-loop, all-PMMA IOL, marketed as “Universal” style (Pannu lens). Manufacturer: Unknown. Interval implantation/death of donor: Unknown. However, as this lens is not in use since the late 1980s, we assume the interval was approximately 20 years. Laboratory analyses: High-resolution anterior segment magnetic resonance imaging (MRI) of the enucleated eye; gross analyses of the anterior segment of the eye from the posterior and anterior views; gross and light microscopic analyses of the lens after explantation; and histopathological analysis of the donor eye. MRI examination of the whole eye revealed the presence of an IOL with features mostly characteristic of a posterior chamber lens, but implanted in the anterior chamber with loops fixated to the angle. The optic was in a plane slightly anterior to the loops, which seemed to be pushing onto the iris (Figure 2, arrow). The frontal MRI view (Figure 3) showed the loops in a counter-clockwise configuration. The lens was fairly centered in relation to the pupil. Figure 2 Figure 3 Gross examination of the anterior segment from anterior (Figures 4 and 5) and posterior (Figures 6 and 7) views showed significant pigmentary dispersion, pupil ovalization, and peripheral anterior synechia formation. Two surgical iridectomies were apparently performed, and there were relatively large areas of transillumination defects, some of which coincided with the point at which the rings at the extremities of the loops were in contact with the iris (arrows). Figure 4 Figure 6 Figure 5 Figure 7 Gross (Figure 8) and light microscopy (Figures 9, 10, and 11) of the lens revealed the presence of iris pigments throughout the surface of the lens. One of the loops was incarcerated within the iris tissue, which remained attached to its surface upon explantation (arrows). Figure 9 Figure 10 Figure 8 Figure 11 Histopathological examination of multiple sections obtained from the enucleated eye showed that the cornea was thick, with a significant attenuation of the corneal endothelium (Figures 12, and 13; PAS stain). The anterior chamber angle exhibited areas of marked enlargement (Figure 14; PAS stain), while other areas had peripheral anterior synechiae. Cornea Cornea Corneal endothelium Figure 12 Figure 13 Iris Figure 14 Histopathological examination of multiple sections obtained from the enucleated eye also showed significant vacuolization within the pigmented epithelium of the iris (Figures 15 and 16; PAS stain). The basement membrane of the ciliary body epithelium was somewhat thick, which may indicate long-standing diabetes (Figure 17; PAS stain; arrow). Iris Iris Figure 15 Figure 16 Figure 17 Because the Pannu IOL may still be observed clinically on occasion, this report sought to present its history and pathological features. This case suggests that the IOL may remain well-centered over the long term, when implanted into the anterior chamber. However, gross and histopathological examination revealed that the overall design and fixation mechanism of the lens caused long-term trauma with significant pigmentary dispersion, among other issues. Although unknown in this donor, development of further complications, such as pigmentary glaucoma remains a possibility. The Pannu “Universal” IOL has design features which are overall those of a posterior chamber lens. Interestingly, some surgeons worldwide would still implant posterior chamber lenses in the anterior chamber in cases lacking capsular support,4 despite clinical studies describing complications such as loop encapsulation by peripheral anterior synechiae, recurrent iritis, central loop displacement with corneal endothelial touch, progressive endothelial cell loss and corneal edema, glaucoma, and cystoid macular edema.5 In conclusion, the Pannu universal IOL has probably not been implanted in the US since the late 80s. This study shows long-term biologic consequences due to its overall design and mechanism of fixation. Our findings are relevant, considering more recent anecdotal reports of implantation of posterior 1. 2. 3. 4. 5. Pannu JS, inventor. Universal intraocular lens and a method of measuring an eye chamber size. US patent 4,435,855. March 13, 1984. Pannu JS. Technique for fixating a subluxated posterior chamber lens. J Cataract Refract Surg 1988; 14:688-690. Pannu JS. A new suturing technique for ciliary sulcus fixation in the absence of posterior capsule. Ophthalmic Surg 1988; 19:751-754. Hara T, Hara T. Ten-year results of anterior chamber fixation of the posterior chamber intraocular lens. Arch Ophthalmol 2004; 122:1112-1116. Koch DD, Wang L. Complications of anterior chamber fixation of posterior chamber intraocular lenses. Arch Ophthalmol 2006; 124:606-607; author reply.