COVER STORY The Safety of Iris-Fixated Designs

Strict inclusion criteria for implantation must be applied.

BY MURIEL DOORS, MD; AND RUDY M.M.A. NUIJTS, MD, PHD

ris-fixated phakic IOLs have been safely implanted in patients with since 1986.1 The original bicon- cave iris-claw lens, developed in conjunction with Jan I G.F. Worst, MD, of Holland, was updated in 1991 to feature a convex-concave shape. In 1998, the name of the lens changed to the Artisan (Ophtec BV, Groningen, Netherlands; Figure 1). In the following years, hyperopia- and astigmatism-correcting models became available. In 2003, a foldable model of the myopic Artisan, the Artiflex phakic IOL (Ophtec BV; Figure 2), was released in Europe. This lens may offer an advantage over the Artisan because it can be inserted through a smaller incision, with a decrease in surgically induced astigmatism and faster visual recovery.2 Iris-fixated phakic IOLs have provided stable and pre- Figure 1. Eye implanted with an iris-fixated Artisan phakic IOL. dictable visual results.3-7 Summarizing the long-term safe- ty, loss of more than 2 lines of BCVA was detected in only important safety information with regard to implanting 0% to 2.6% of eyes.3-7 Vision-threatening complications iris-fixated phakic IOLs. are rare with the modern Artisan and Artiflex lenses. Overall, the risk of complications is greater in phakic PUPIL SIZE hyperopes than in phakic myopes, due to the shallower The pupil plays an important role in lens centration, nature of the anterior chamber and smaller angle space. which is necessary for optimal optical lens function. The Postimplantation complications of iris-fixated phakic IOLs Artiflex has an optic diameter of 6 mm, whereas the include pupil ovalization, IOL decentration, low-grade Artisan is available with an optic diameter of either 6 mm postoperative uveitis, endothelial cell loss, pupillary-block (for IOL powers up to -15.50 D) or 5 mm (for IOL powers glaucoma, , and retinal detachment; however, all from -16.00 to -24.00 D). If the pupil size in mesopic are rare.3,8-10 lighting conditions exceeds the optical zone diameter of To minimize these complications, an accurate and the phakic IOL, glare and higher-order aberrations could extensive preoperative examination of the patient is of be markedly increased, resulting in decreased visual per- utmost importance. The following sections review some formance and patient satisfaction. This highlights the

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Figure 3. Anterior segment OCT scan of an eye with an implanted iris-fixated phakic IOL showing measured edge- distances (1.46 and 1.34 mm), distance from the center of the phakic IOL to the endothelium (2.11 mm), and distance from the back of the phakic IOL to the natural lens (0.76 mm). Figure 2. Eye implanted with the Artiflex phakic IOL. importance of performing preoperative pupil measure- ments in different lighting conditions. Postoperatively, pupil size is reduced under scotopic con- ditions or medical mydriasis. Dick et al8 showed a mean postoperative scotopic pupil diameter decrease of 1.1 mm in myopic eyes, suggesting that the iris-fixated phakic IOL mechanically restricts pupil size changes under low-light Figure 4. Anterior segment OCT scan with measured central conditions and could reduce the incidence of postopera- corneal thickness (440 µm), anterior chamber depth (3.23 mm), tive photic phenomena. Therefore, we believe that patients angle-to-angle distance (11.96 mm), and lens rise (300 µm). can still be eligible for phakic IOL implantation with a sco- topic pupil size 1 mm larger than the optic of the lens. enlarges with age, the edge distance will decrease over time. To ensure a lifelong safe distance from the phakic ENDOTHELIAL CELL LOSS IOL to the corneal endothelium, the distance between the The long-term effect of iris-fixated phakic IOLs on the edge of the lens and the endothelium should be moni- corneal endothelium remains a point of discussion. The tored yearly using anterior segment imaging. endothelial cell density (ECD) is known to decrease over time, with a physiological rate of 0.6% per year after the LENS RISE AND DECENTRATION age of 18 years.11 Several short-term and a few recent Two recent studies suggest that pigment dispersion on long-term studies have evaluated corneal ECD loss after the phakic IOL and subsequent inflammatory reactions Artisan phakic IOL implantation, showing an average after iris-fixated phakic IOL implantation may be caused ECD loss of 0.7% to 11.7% over 3 years.3,10,12 An anterior by abnormal pressure on the iris.16,17 In this situation, the chamber depth (ACD; measured from the epithelium) of iris is sandwiched between the crystalline lens and the at least 3 mm is suggested as an adequate safety meas- phakic IOL.To minimize chafing of iris tissue (ie, between urement for implantation of the Artisan.3,10 Other safety the phakic IOL and the natural lens) and cataract forma- criteria that have been suggested to maintain a safe dis- tion, there should be enough space between the posteri- tance to the endothelium include a 1.5 mm distance or surface of the phakic IOL and the anterior surface of from the edge of the phakic IOL to the endothelium13 the natural lens. An important preoperative distance and 2 mm from the center of the phakic IOL to the concerning these complications is the lens rise, which is endothelium,14 both of which can be measured using the distance from the anterior surface of the crystalline anterior segment imaging (Figure 3). lens to the horizontal line between the two angle recess- In a recent study at our institution,15 we found that a es (Figure 4). Baikoff et al17 suggest that the preoperative shorter distance from the edge of the phakic IOL to the lens rise should be less than 600 µm to avoid pigment endothelium was associated with higher ECD loss. For dispersion. This distance can be easily measured using an example, for an edge distance of 1.37 mm, a linear mixed- anterior segment imaging device. model analysis predicted an ECD loss of 0.98% per year. Lens decentration, which may develop spontaneously, However, an edge distance of 1.15 mm resulted in a yearly is often due to an inadequate amount of iris tissue ECD loss of 1.8%, and an edge distance of 1.59 mm result- enclavation. However, decentration can also occur after ed in a yearly loss of only 0.15%. Because the natural lens blunt trauma, which may result in loosening of the hap-

FEBRUARY 2010 I CATARACT & REFRACTIVE SURGERY TODAY EUROPE I 53 COVER STORY

A CONCLUSION Iris-fixated phakic IOLs safely and effectively correct myopia, hyperopia, and astigmatism when strict inclu- sion criteria for implantation are applied. In addition to yearly ECD counts, it is important to perform anterior segment imaging to evaluate the distance from the pha- kic IOL to the endothelium and crystalline lens to make sure these lenses will be safe in the long term. ■

Muriel Doors, MD, is a resident in the Department of Ophthalmology, Maastricht University Medical Center, Netherlands. Dr. Doors states that she has no financial interest in the products or companies mentioned. She may be reached at tel: +31 43 3877346; fax: +31 43 3875343; e-mail: [email protected]. B Rudy M.M.A. Nuijts, MD, PhD, is an Associate Professor of Ophthalmology in the Department of Ophthalmology at Academic Hospital, Maastricht, Netherlands. He is a member of the CRST Europe Editorial Board. Dr. Nuijts states that he has no financial interest in the products or companies mentioned. He may be reached at e-mail: [email protected].

1. Fechner PU, van der Heijde GL, Worst JG. The correction of myopia by lens implantation into phakic eyes. Am J Ophthalmol. 1989;107:659-663. 2. Kohnen T, Cichocki M, Koss MJ. Position of rigid and foldable iris-fixated myopic phakic intraocular lenses evaluated by Scheimpflug photography. J Cataract Refract Surg. 2008;34:114-120. 3. Budo C, Hessloehl JC, Izak M, et al. Multicenter study of the Artisan phakic . J Cataract Refract Surg. 2000;26:1163-1171. 4. Tahzib NG, Nuijts RM, Wu WY, Budo CJ. Long-term study of Artisan phakic intraocular Figure 5. (A) Short- and (B) long-term follow up.The patient lens implantation for the correction of moderate to high myopia: ten-year follow-up results. Ophthalmology. 2007;114:1133-1142. presented with shifting of one haptic on long-term follow-up. 5. Stulting RD, John ME, Maloney RK, Assil KK, Arrowsmith PN, Thompson VM. Three-year results of Artisan/Verisyse phakic intraocular lens implantation. Results of the United States Food And Drug Administration clinical trial. Ophthalmology. 2008;115:464-472. tic or haptics. The need for refixation depends on the 6. Guell JL, Morral M, Gris O, Gaytan J, Sisquella M, Manero F. Five-year follow-up of 399 amount of decentration, the patient’s vision, glare com- phakic Artisan-Verisyse implantation for myopia, hyperopia, and/or astigmatism. Ophthalmology. 2008;115:1002-1012. plaints, and—most important—the risk of endothelial 7. Silva RA, Jain A, Manche EE. Prospective long-term evaluation of the efficacy, safety, and damage. We described a case series of 368 eyes in which stability of the phakic intraocular lens for high myopia. Arch Ophthalmol. 2008;126:775-781. 8. Dick HB, Aliyeva S, Tehrani M. Change in pupil size after implantation of an iris-fixated nine eyes (2.4%) presented with late-onset sliding of the toric phakic intraocular lens. J Cataract Refract Surg. 2005;31:302-307. haptics through the iris tissue (Figure 5).18 Decentration 9. Kleinmann G, Apple DJ, Mackool RJ. Recurrent iritis after implantation of an iris-fixated phakic intraocular lens for the correction of myopia Case report and clinicopathologic corre- was discovered at a mean follow-up of 4.8 years (range, lation. J Cataract Refract Surg. 2006;32:1385-1387. 3–7 years). Mean downward decentration was 0.28 ±0.15 10. Landesz M, van Rij G, Luyten G. Iris-claw phakic intraocular lens for high myopia. J Refract Surg. 2001;17:634-640. mm. The distance from the edge of the phakic IOL to the 11. Bourne WM, Nelson LR, Hodge DO. Central corneal endothelial cell changes over a ten- corneal endothelium was measured using anterior seg- year period. Invest Ophthalmol Vis Sci. 1997;38:779-782. 12. Benedetti S, Casamenti V, Benedetti M. Long-term endothelial changes in phakic eyes ment optical coherence tomography (OCT), with mean after Artisan intraocular lens implantation to correct myopia: five-year study. J Cataract edge distances measured on the nasal, temporal, superi- Refract Surg. 2007;33:784-790. 13. Baikoff G. Anterior segment OCT and phakic intraocular lenses: a perspective. J Cataract or, and inferior sides of 1.71 ±0.30 mm, 1.86 ±0.31 mm, Refract Surg. 2006;32:1827-1835. 1.86 ±0.31 mm, and 1.58 ± 0.34 mm, respectively. Mean 14. Guell JL, Morral M, Gris O, Gaytan J, Sisquella M, Manero F. Evaluation of Verisyse and Artiflex phakic intraocular lenses during accommodation using Visante optical coherence enclavated iris tissue on the nasal and temporal sides was tomography. J Cataract Refract Surg. 2007;33:1398-1404. smaller after decentration when compared with that 15. Doors M, Cals DW, Berendschot TT, et al. Influence of anterior chamber morphometrics on endothelial cell changes after phakic intraocular lens implantation. J Cataract Refract directly after surgery (P =.033 and P =.017, respectively). Surg. 2008;34:2110-2118. 16. Alio JL, Mulet ME, Shalaby AM. Artisan phakic iris claw intraocular lens for high primary Shifting of the haptics did not result in decreased UCVA and secondary hyperopia. J Refract Surg. 2002;18:697-707. or BCVA, and there were no glare complaints. Refixation 17. Baikoff G, Bourgeon G, Jodai HJ, et al. Pigment dispersion and Artisan phakic intraocular lenses: crystalline lens rise as a safety criterion. J Cataract Refract Surg. 2005; 31:674-680. was not indicated in any of the patients; however, careful 18. Doors M, Eggink FA, Webers CA, Nuijts RM. Late-onset decentration of iris-fixated pha- follow-up will be required to detect early ECD losses. kic intraocular lenses: a case series. Am J Ophthalmol. 2009;147:997-1003.

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