Ophthalmic Surgery, Lasers and Imaging Retina

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Case Report 

Scanning Electron Microscopic and Energy Dispersive Spectroscopic Findings of a Removed Iris-Claw Lens

Hulya Gungel, MD; Deniz Oygar Baylancicek, MD

Abstract

A case of a patient whose phakic iris-claw lens fell into the anterior chamber after 15 years of implantation are reported. The surface of the lens was analyzed with scanning electron microscopy and with energy dispersive spectroscopy. Granular aggregates on the anterior surface and denser aggregates branching into wide areas on the posterior surface of the optic, irregularities on interface surfaces of the haptics due to possible manufacturing defects, and impressions due to devices used for implantation were detected, as were calcium (Ca) deposits in the aggregates. Considering the facilitated damage and atrophy of the iris by the irregularities of the interface surface of the haptics and also the dense Ca deposits on the surfaces which affect biocompatibility, it would be better to exchange the old lens, which has fallen into the anterior chamber, for a new generation one instead of reimplanting the older lens that has been in position for many years.

Abstract

A case of a patient whose phakic iris-claw lens fell into the anterior chamber after 15 years of implantation are reported. The surface of the lens was analyzed with scanning electron microscopy and with energy dispersive spectroscopy. Granular aggregates on the anterior surface and denser aggregates branching into wide areas on the posterior surface of the optic, irregularities on interface surfaces of the haptics due to possible manufacturing defects, and impressions due to devices used for implantation were detected, as were calcium (Ca) deposits in the aggregates. Considering the facilitated damage and atrophy of the iris by the irregularities of the interface surface of the haptics and also the dense Ca deposits on the surfaces which affect biocompatibility, it would be better to exchange the old lens, which has fallen into the anterior chamber, for a new generation one instead of reimplanting the older lens that has been in position for many years.

Scanning Electron Microscopic and Energy Dispersive Spectroscopic Findings of a Removed Iris-Claw Lens

From the Beyoglu Eye Education and Research Hospital 4. Eye Clinic, Istanbul, Turkey.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to Deniz Oygar Baylancicek, MD, Beyoğlu Göz Eğitim ve Arastirma Hastanesi, 4. Goz Klinigi, Kuledibi-Istanbul-Turkiye.

Accepted: December 02, 2008
Posted Online: March 09, 2010

Introduction

Iris-fixated lenses are used to correct refractive errors in aphakic and phakic cases. The original iris-claw lens design was introduced by Jan Worst in 1978; this design is still used for phakic correction of ametropias1. This lens attaches to the peripheral iris. The enclavation techniques of these well-known lenses were reported repeatedly in the literature.2–9 Iris atrophy, pigment discharge, iritis, endothelial cell loss, blood-aqueous barrier breakdown, and dropping into the anterior chamber are the reported complications.7,9

In this case report, our aim was to share the results of a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses of a polymethyl mehocyslate (PMMA) phakic iris-claw lens implanted 15 years ago and removed in our clinic after a second drop of the lens into the anterior chamber.

Case Report

A 56-year-old man presented with diminution of vision of 2 weeks in the right eye in May 2006. He had high myopia and had undergone implantation of a phakic iris-claw lens 15 years ago. He did not have any trauma in his history. This was the second dropping of the iris-claw lens into the anterior chamber in the last year.

The iris-claw lens had been reimplanted after its first dropping in another centre. The patient had a best-corrected visual acuity of 0.05 in the right eye and 0.5 in the left. Biomicroscopic examination showed minimal corneal edema, total dislocation of the iris-claw lens into the anterior chamber where it leaned against the iris, rupture and atrophy in the periphery of the iris, a round pupilla, minimal pigmentation on the anterior surface of the lens and nuclear sclerosis. Degenerative myopia was detected in funduscopic examination.

The iris-claw lens was removed because iris tissue damage prevented reimplantation. The lens was kept tographs were taken and EDS examinations were carried out from the anterior and posterior surfaces of the optic and haptics.

The opacities, mostly Ca, sodium (Na) and nitrogen (N), were of the granular type on the anterior optic surface and optic haptic junctions (Fig. 1) and spread by branching and producing protuberances in large areas on the posterior optic surface of the iris-claw lens (Fig. 2). SEM showed irregularities and instrument pressure signs on the haptic surfaces of this intra ocular lense (IOL) and that the posterior surface had been covered by a membrane (Figs. 3A and 3B).

(A) Electron Microscopy of the Anterior Surface of the Iris-Claw Lens. (B) Energy Dispersive Spectroscopy of the Deposits on the Optic-Haptic Junction. (C) Energy Dispersive Spectroscopy of the Granular Deposits on the Anterior Surface.

Figure 1. (A) Electron Microscopy of the Anterior Surface of the Iris-Claw Lens. (B) Energy Dispersive Spectroscopy of the Deposits on the Optic-Haptic Junction. (C) Energy Dispersive Spectroscopy of the Granular Deposits on the Anterior Surface.

(A) Electron Microscopy of Deposits on Posterior Surface of Iris-Claw Lens. (B) a Deposit that Made Protuberances from the Surface. (C) Deposits that had Spread in a Large Area by Branching. (D) Energy Dispersive Spectroscopy of the Protuberated Deposit. (E) Energy Dispersive Spectroscopy of the Branched Deposits.

Figure 2. (A) Electron Microscopy of Deposits on Posterior Surface of Iris-Claw Lens. (B) a Deposit that Made Protuberances from the Surface. (C) Deposits that had Spread in a Large Area by Branching. (D) Energy Dispersive Spectroscopy of the Protuberated Deposit. (E) Energy Dispersive Spectroscopy of the Branched Deposits.

(A) Electron Microscopy of Haptic Surfaces of the Iris-Claw Lens Covered with a Membrane. (B) Electron Microscopy of Haptic Surfaces of the Iris-Claw Lens Showing Impressions.

Figure 3. (A) Electron Microscopy of Haptic Surfaces of the Iris-Claw Lens Covered with a Membrane. (B) Electron Microscopy of Haptic Surfaces of the Iris-Claw Lens Showing Impressions.

Discussion

In the literature, depigmentation of the iris stroma, pupil ovalization, iris atrophy at the site of fixation, and total dislocation were reported. A new generation model of the phakic iris-fixated IOL with thin optics, flexible haptics and a convex-concave design has been reported to have fewer complications.10,11 Partial or total dislocations should be treated urgently due to the risk of endothelial damage.11–14 Depending on iris damage, the lens could be reenclavated or removed.

In our case, the iris-claw lens had been implanted 15 years ago and had dropped into the anterior chamber twice in one year. After the first drop, the lens was reenclavated, but after the second drop it was removed due to wide tissue damage. The possible induction of chronic subclinical inflammation was evaluated after implantation of the iris-claw lens because of close proximity to the iris. Using fluorophotometry, an increase in the permeability of the blood-aqueous barrier after implantation has been reported.7 It has been known for years that the surface irregularities of haptics in sulcus fixation that have contact with uveal tissue can trigger this type of inflammation.

In SEM analysis of the iris-claw lens removed from the case, there was no deformity on the optic edges, whereas irregularities on the surfaces of the haptic were striking. These irregularities, which were in close proximity to the iris, may be due to manufacturing defects or impressions of the devices after multiple surgeries. Also, surgical manipulations could form impressions on the surfaces. On the anterior surface, optic-haptic junctions are the most manipulated regions; in this case, dense aggregates were observed in these regions. Also, coating of the posterior surfaces of the haptics with a membrane was detected. No irregularities, particularly at the optic anterior and posterior surfaces, optic edge, haptic, and the optic/haptic junctions were detected by SEM and EDS analyses of the following unused new generation phakic IOLs: angle-fixated anterior chamber lens Chiron Vision Nu Vita MA 20 (PMMA), iris-fixated anterior chamber lens Ophtec Artisan Iris Claw (PMMA), posterior chamber lens Staar ICM (polymer from porcine collagen and 2-hydroxyethyl methacrylate). Haptic surfaces of the new generation iris-claw lenses (PMMA) were detected as smooth and homogenous. It was also reported that new generation lenses were more advantageous regarding tissue inflammation and other complications.8 Although dislocation could be the result of poorly fitted lenses during surgery, we should consider that the irregularities on the surfaces of the haptics could also have caused dislocation due to iris atrophy and defect by facilitating chronic subclinical inflammation.

In the EDS analysis of the removed rigid iris claw lens, aggregates on the two optic surfaces—denser on the posterior—were detected. In the EDS findings of the aggregates that formed protuberances on the posterior surface, N (representing protein) and Ca were detected. Lots of protein deposited on the posterior surface could probably cause the Ca deposition. Aggregates containing inflammatory cells, pigmented cells and debris on the posterior surface of the optic of the iris-claw lens removed from a case with recurrent iritis were shown.7 Ca deposition could disturb the biocompatibility, but in our case Ca deposition on the lens did not cause any opacification, so could not be the cause for removal.

Conclusion

In light of recent reported studies, the possibility of dislocation of the iris-claw lens is a complication that should be kept in mind whereas performing implantation of these phakic IOLs for refractive correction. In the literature, we could not find any reports about SEM and EDS analyses of a high biocompatibility PMMA lens removed from the eye after many years. To the best of our knowledge, this was the first report showing surface analyses using EDS and SEM of an iris-claw lens removed after 15 years. The possible manufacturing or traumatic origin defects and the other irregularities on the haptic surfaces could cause tissue damage and therefore dislocation after a long time. Also, this may have facilitated the second drop of the lens. Further study of such lenses is required. Considering the intense accumulation of Ca on the surfaces and the possible manufacturing or traumatic defects in the haptics of old generation iris-claw lens, an iris-claw lens dislocated after many years should be removed and replaced with a new generation one, if possible, instead of repositioning the same IOL.

References

  1. Saxena R, Landest M, Noordzij B, Luyten GP. Three-year follow-up of the Artisan phakic intraocular lens for hypermetropia. Ophthalmology. 2003;110:1391–1395. doi:10.1016/S0161-6420(03)00405-6 [CrossRef]
  2. Fechner PU, Haubitz I, Wichmann W, Wulff K. Worst-Fechner biconcave minus power phakic iris-claw lens. J Refract Surg. 1999;15:93–105
  3. Neuhann IM, Kleinmann G, Apple DJ, Pandey SK, Neuhann TF. Cocooning of an iris-fixated intraocular lens in a 3-year-old child after perforating injury: clinicopathologic correlation. J Cataract Refract Surg. 2005Sep;31(9):1826–1828. doi:10.1016/j.jcrs.2005.06.009 [CrossRef]
  4. Menezo JL, Martinez MC, Cisneros AL. Iris-fixated Worst claw versus sulcus-fixated posterior chamber lenses in the absence of capsular support. J Cataract Refract Surg. 1996;22:1476–1484.
  5. El Danasoury MA, El Maghraby A, Gamali TO. Comparison of iris-fixed Artisan lens implantation with excimer laser in situ keratomileusis in correcting myopia between −9.00 and −19.50 diopters: a randomized study. Ophthalmology. 2002;109:955–964. doi:10.1016/S0161-6420(02)00964-8 [CrossRef]
  6. Singhal S, Sridhar MS. Late spontaneous dislocation (disenclavation) of iris-claw intraocular lenses. J Cataract Refract Surg. 2005;31: 1441–1443. doi:10.1016/j.jcrs.2004.11.045 [CrossRef]
  7. Pérez-Santonja JJ, Bueno JL, Zato MA. Surgical correction of high myopia in phakic eyes with Worst-Fechner myopia intraocular lenses. J Refract Surg. 1997;13:268–81; discussion 281–284.
  8. Budo C, Hessloehl JC, Izak M, Luyten GP, Menezo JL, Sener BA, Tassignon MJ, Termote H, Worst JG. Multicenter study of the Artisan phakic intraocular lens. J Cataract Refract Surg. 2000;26:1163–1171. doi:10.1016/S0886-3350(00)00545-9 [CrossRef]
  9. Risco JM, Cameron JA. Dislocation of a phakic intraocular lens. Am J Ophthalmol. 1994;15:118:666–667.
Authors

From the Beyoglu Eye Education and Research Hospital 4. Eye Clinic, Istanbul, Turkey.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to Deniz Oygar Baylancicek, MD, Beyoğlu Göz Eğitim ve Arastirma Hastanesi, 4. Goz Klinigi, Kuledibi-Istanbul-Turkiye.

10.3928/15428877-20100215-09

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