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Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses
ARTICLE
Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses Lorenz Vock, MD, JD, Rupert Menapace, MD, Eva Stifter, MD, Wolf Bu¨hl, MD, Michael Georgopoulos, MD
PURPOSE: To evaluate the effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the clinical performance of a single-piece hydrophilic acrylic intraocular lens (IOL) with haptic angulation. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: A prospective study of 52 patients with bilateral age-related cataract was conducted. Patients had standard cataract surgery with implantation of the same IOL in both eyes. Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. Assessed parameters were visual axis opacification (VAO) in eyes with a PCCC or regeneratory posterior capsule opacification (PCO) in eyes without PCCC (scale 0 to 10) in the central (3.0 mm eccentricity), intermediate (3.0 to 4.5 mm eccentricity), and peripheral (>4.5 mm eccentricity [capsulorhexis edge]) areas; neodymium:YAG (Nd:YAG) laser capsulotomy or laser polishing of ongrowing lens epithelium; anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity. RESULTS: Thirty patients completed the 2½-year follow-up. Visual axis opacification was significantly lower in the central region in the PCCC group (mean 0.5 G 0.7 [SD]) than PCO in the central region of the non-PCCC group (mean 1.1 G 1.1) (P Z .02). Forty percent in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period; none in the PCCC group had laser polishing. There were no significant differences in ACO, SE, BCVA, or contrast sensitivity. There was no additional gain in BCVA or contrast sensitivity in eyes with a PCCC compared with eyes without a PCCC when VAO and PCO were low. CONCLUSION: A PCCC significantly reduced PCO formation within the central 3.0 mm eccentricity as well as the need for Nd:YAG laser capsulotomy in eyes with a single-piece hydrophilic acrylic IOL with angulated haptics. J Cataract Refract Surg 2007; 33:628–634 Q 2007 ASCRS and ESCRS
Currently, an effective way to prevent posterior capsule opacification (PCO) is to implant intraocular lenses (IOLs) with sharp posterior optic edges.1–7 However, the barrier effect of a sharp posterior optic edge may fail. In primary posterior curvilinear capsulorhexis (PCCC), the central part of the posterior capsule is removed during cataract surgery to prevent equatorial lens epithelial cell (LEC) migration onto the posterior capsule from reaching the visual axis. It was first recommended by Castaneda et al.8 and is frequently used to prevent more severe PCO formation in children’s eyes 9–11 in combination with 628
Q 2007 ASCRS and ESCRS Published by Elsevier Inc.
anterior vitrectomy or posterior optic capture.12,13 In adults, the PCCC technique is less frequently performed but is particularly useful in the management of intraoperative capsule tears.14 However, ongrowth of LECs over the PCCC rim onto the posterior surface of the IOL and secondary closure of the PCCC have been reported.15,16 Several methods of IOL optic capture to avoid secondary PCCC reclosure have been proposed.17,18 Georgopoulos et al.19 report that the benefit of a PCCC in reducing central PCO in adults is dependent on the IOL material because posterior ongrowth is found 0886-3350/07/$dsee front matter doi:10.1016/j.jcrs.2007.01.007
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Figure 1. Posterior capsule opacification evaluation areas. a: Peripheral, 4.5 mm (projected) margin of the ACCC eccentricity. b: Intermediate, 3.0 to 4.5 mm eccentricity. c: Central, 3.0 mm eccentricity.
more often on hydrogel IOL optics than on silicone optics. Little is known about the performance of a PCCC in eyes with IOLs with sharp optic edges and angulated haptics. Thus, we evaluated the effectiveness of a PCCC in eyes with a hydrophilic IOL with a sharp optic edge and 10-degree angulated haptics in a prospective randomized trial with an intrapatient design.
PATIENTS AND METHODS Fifty-two patients with bilateral age-related cataract were included in the trial. All had surgery in both eyes after exclusion for pseudoexfoliation syndrome, glaucoma, uveitis, and proliferative diabetic retinopathy. The trial was approved by the Ethics Committee of the Medical University of Vienna. All procedures were covered by the tenets of the Helsinki Declaration, and all patients provided informed consent.
Intraocular Lens The ACR6D SE (Laboratoires Corne´al) is a single-piece IOL of a hydrophilic acrylic copolymer of 2-hydroxyethyl methacrylate and ethyl methacrylate with a water content of 26%. It has an optic diameter of 6.0 mm and an overall length of 12.0 mm. The ACR6D SE IOL has 10-degree angulated haptics. The A-constant used with optical biometry was 120.
Accepted for publication January 3, 2007. From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. No author has a financial or proprietary interest in any material or method mentioned. Corresponding author: Rupert Menapace, MD, Department of Ophthalmology, Medical University of Vienna, Wa¨hringer Gu¨rtel 18-20, A-1090 Wien, Austria. E-mail: [email protected].
Surgical Technique All surgeries were performed in a standardized fashion by the same experienced surgeon (R.M.) using topical anesthesia and a 3.2 mm temporal self-sealing limbo-corneal tunnel incision. A well-centered, round, anterior continuous curvilinear capsulorhexis (ACCC) with a 5.0 mm diameter was aimed for to ensure appropriate overlap of the IOL optic. After hydrodissection and phacoemulsification were performed, a well-centered round PCCC with a diameter smaller than the ACCC was torn with a capsule forceps in the selected eye of the patient. The target diameter was 4.0 mm. The surgical technique used to ensure precise PCCC sizing has been described in detail.18 Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. An ophthalmic viscoelastic device (OVD) (hyaluronic acid 5000 10 mg/mL [Healon]) was used. Until the completion of cortex removal, the surgeon was unaware whether a PCCC would be made. After IOL implantation, the OVD was removed from the anterior chamber by irrigation/aspiration (I/A). In non-PCCC eyes, the retro-optical OVD was also aspirated by tilting up the optic and directly accessing the retrolental space with the coaxial I/A tip. In the PCCC eyes, the OVD was removed from the capsular bag periphery, but inherently not from behind the optic.20 Postoperative treatment consisted of prednisolone acetate (Ultracortenol) and diclofenac sodium (Voltaren) eyedrops 4 times a day for 4 weeks.
Image Analysis At the 2½-year follow-up, visual axis opacification (VAO), PCO, and the sizes of the ACCC and PCCC were assessed using digital retroilluminated photographs21 taken after maximum pupil dilation with a digital camera (NC2000, Kodak). The PCO and VAO were quantified using the Automated Quantification of After-Cataract (AQUA) system,22 which was developed in Vienna and defines 3 areas of evaluation (Figure 1).
Slitlamp Examination At 2½ years, the behavior of LECs at the PCCC rim was assessed at the slitlamp in eyes with a PCCC using the following categories: (1) free PCCC rim, (2) ruffled PCCC rim, and (3) posterior ongrowth (Figure 2). The number of neodymium:YAG (Nd:YAG) laser capsulotomies or Nd:YAG laser polishing of LEC ongrowth onto the optic surface
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Figure 2. Behavior of LECs at the PCCC. A: Free PCCC rim. B: Ruffled PCCC rim. C: Posterior ongrowth (arrows) PCCC rim. within the PCCC performed during the follow-up was recorded, and cases of buttonholing of the ACCC and PCCC were counted. Anterior capsule opacification (ACO) was assessed as being present (yes) or not present (no) and categorized by morphology as ACO of the capsulorhexis edge or ACO of the entire capsulorhexis leaf (ie, diffuse). Gaps between the anterior capsule leaf and the IOL optic (anterior capsule gaping) were subjectively categorized at the slitlamp as being present (yes) or not present (no). Best corrected visual acuity (BCVA) was assessed monocularly using a standard set of corrective lenses and Snellen charts under standardized conditions. Contrast sensitivity was tested using a standard Ginsburg box (VSCR-CST 1800) with a Functional Acuity Contrast Test (FACT) chart at 6 cd/m2 and at spatial frequencies of 1.5 to 18 cycles per degree (cpd). The last patch of the FACT chart the patient correctly identified before 2 consecutive errors was used to calculate the contrast sensitivity of that spatial frequency. The contrast sensitivity scores were transformed into logarithmic values for statistical analysis. A difference level of 0.15 logCSF23 (corresponding 1 patch in the chart) between the groups at a given spatial frequency was deemed clinically relevant.
Statistical Analysis Because of the intraindividual design of the study, paired tests were performed. Numeric and scaled data were analyzed using Friedmann and Wilcoxon tests. Paired categorized data were analyzed with McNemar chi-square tests and unpaired data, with standard chi-square tests. P values of proportions within the group with a PCCC were evaluated with the binomial distribution function. An a level of 0.05 was considered statistically significant. Eyes that had Nd:YAG treatment were excluded from the statistical analysis of
AFTER CATARACT [AQUA]
peripheral
intermediate
BCVA and contrast sensitivity. In the assessment of VAO and PCO, the central AQUA scores of Nd:YAG laser-treated eyes were estimated using the peripheral scores of the eyes.
RESULTS The mean patient age at surgery was 74 years G 10 (SD) (range 52 to 90 years). Thirty patients were available at the follow-up, 7 men (23%) and 23 women (77%). The mean follow-up was 2.4 G 0.4 years (range 1.6 to 3.7 years). Forty percent of eyes in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period, but no eye in the PCCC group had laser polishing. Visual axis opacification was significantly lower in the central region in the PCCC eyes than PCO in the central region in the non-PCCC eyes (Figure 3). No significant differences were found in ACO, anterior capsule gaping, or spherical equivalent (SE) or in BCVA or contrast sensitivity after exclusion of the eyes with Nd:YAG laser capsulotomy (Tables 1 and 2 and Figure 4). DISCUSSION In this prospective randomized trial, the impact of a PCCC on the clinical performance of a single-piece central p = 0.003
4.0
Figure 3. AQUA scores in eyes with and without PCCC in the central 3.0 mm eccentricity, intermediate 3.0 to 4.5 mm eccentricity, and peripheral 4.5 mm (projected) margin of the ACCC eccentricity (Figure 1) ( Z outliers; * Z extreme values).
2.0
0.0 PCCC no PCCC
PCCC no PCCC
PCCC no PCCC
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Table 1. Clinical parameters after 2½ years. Parameter VAO/PCO Central Mean G SD Median 95% CI Intermediate Mean G SD Median 95% CI Peripheral Mean G SD Median 95% CI Nd:YAG, n (%) Mean ACCC area (mm2) G SD Snellen BCVA (logMAR)* Mean G SD Median 95% CI CS (log)* 1.5 cpd Mean G SD Median 95% CI 3 cpd Mean G SD Median 95% CI 6 cpd Mean G SD Median 95% CI 12 cpd Mean G SD Median 95% CI 18 cpd Mean G SD Median 95% CI ACO, n (%) ACO pattern, n (%) Capsulorhexis edge Diffuse ACG SE (D) Mean G SD Median 95% CI
No PCCC
PCCC
1.1 G 1.1 0.9 0.6 to 1.5
0.5 G 0.7 0.2 0.2 to 0.7
1.4 G 0.9 1.1 1.1 to 1.7 1.5 G 0.9 1.3 1.1 to 1.8
1.4 G 0.9 1.2 1.1 to 1.8
12 (40) 16.0 G 3.0
1.7 G 0.9 1.7 1.3 to 2.0 0 16.2 G 3.2
0.10 G 0.11 0.10 0.17 to 0.03
0.10 G 0.13 0.12 0.16 to 0.05
n
P Value
29
.003
29
.83
29
.39
30 30 14/26
!.0001 .8 .96
17/26 .61 1.41 G 0.22 1.55 1.29 to 1.52
1.49 G 0.23 1.55 1.40 to 1.59
1.27 G 0.63 1.46 0.94 to 1.59
1.47 G 0.60 1.67 1.22 to 1.71
1.11 G 0.77 1.36 0.72 to 1.51
1.35 G 0.63 1.58 1.09 to 1.60
0.38 G 0.55 0.0 0.1 to 0.66
0.65 G 0.64 0.90 0.39 to 0.91
0.11 G 0.26 0.0 0.1 to 0.25 17 (57)
0.26 G 0.44 0.0 0.08 to 0.44 14 (47)
.28
.87
.19
.09
11 (37) 4 (13) 24 (80) 0.99 G 1.02 1.0 1.38 to 0.59
11 (37) 3 (10) 25 (83)
30 30
.43 .92
30 28
0.74 0.85
1.04 G 1.08 0.93 1.46 to 0.62
ACCC Z anterior continuous curvilinear capsulorhexis; ACG Z anterior capsule gaping; ACO Z anterior capsule opacification; BCVA Z best corrected visual acuity; CI Z confidence interval; cpd Z cycles per degree; CS Z contrast sensitivity function; PCCC Z primary posterior continuous capsulorhexis, PCO Z posterior capsule opacification; Nd:YAG Z neodymium:YAG capsulotomy; SE Z spherical equivalent; VAO Z visual axis opacification *Nd:YAG treated eyes excluded
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without a PCCC (0.6 AQUA units) (P Z .003) when a hydrophilic IOL with sharp optic edges and 10-degree angulated haptics was implanted. In both groups, PCO in the peripheral and intermediate areas remained equally high and was not significantly different. In the intermediate area in the PCCC eyes, LECs accumulated around the PCCC rim and posterior ongrowth occurred, which were responsible for higher AQUA scores than in the central region. In the non-PCCC eyes, high PCO scores in the intermediate area were the result of the normal migration of LECs onto the posterior capsule. The number of Nd:YAG laser capsulotomies was high in the nonPCCC group; thus, the effect of the sharp optic edge of the hydrophilic acrylic IOL with haptic angulation and broad haptic junctions was insufficient to prevent vision-disturbing PCO in two fifths of the cases. Despite the hydrophilic material, the presence of a PCCC could have significantly reduced central VAO in the PCCC group. Still, many cases of ruffled PCCC rims and posterior ongrowth were seen, which presumably are linked to the good biocompatibility of the hydrophilic material with regard to LECs. Further follow-up is necessary determine whether IOLs with a ruffled PCCC rim develop posterior ongrowth later.
Table 2. Behavior of LECs at the PCCC rim. Parameter
Yes
No
N
P Value
Free rim Ruffled rim Posterior ongrowth
17 10 3
13 20 27
30 d d
.58 .09 .000008
hydrophilic acrylic IOL with a sharp posterior edge (ACR6D SE) was evaluated. It was shown that in eyes with this type of IOL, a PCCC significantly reduced central PCO as well as the need for Nd:YAG treatment. Eyes with a PCCC required no Nd:YAG capsule polishing, while 40% of without a PCCC required Nd:YAG laser capsulotomy. Visual Axis and Posterior Capsule Opacification and Neodymium:YAG Treatment The development of PCO is dependent on many factors24 including the IOL optic edge,1–7 material,25,26 or haptic junction.27,28 In particular, with single-piece IOLs, the barrier effect of the sharp optic edge is often reduced at broad haptic junctions, allowing ongrowth of LECs onto the posterior capsule.26 Material properties of IOLs also seem to influence the performance of a PCCC; Georgopoulos et al.19 found less posterior ongrowth with silicone IOLs than with hydrogel IOLs, both of which have open-loop haptics and do not have sharp posterior edges. Little, however, is known about the effects of a PCCC in eyes with IOLs with sharp optic edges and angulated haptics. In our study, the presence of a PCCC significantly reduced central VAO compared with PCO in eyes 1.5 cpd
3 cpd
6 cpd
°
2.00
CSF [log]
Best Corrected Visual Acuity and Contrast Sensitivity Neither BCVA nor contrast sensitivity were significantly different between the PCCC group and the non-PCCC group. This result is biased by the high number of Nd:YAG treatments in the non-PCCC group. As Nd:YAG treatment by nature restores BCVA and contrast sensitivity in eyes with previously high PCO,
°
1.50 °
1.00
Figure 4. Contrast sensitivity function (cpd) ( Z outliers; * Z extreme values).
0.50 0.00 PCCC
no PCCC
PCCC
no PCCC
*
*
PCCC
no PCCC
18 cpd
12 cpd
CSF [log]
2.00 1.50
°
1.00 * *
0.50 0.00 PCCC
no PCCC
PCCC
no PCCC
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these eyes had to be excluded from assessment. But excluding Nd:YAG-treated eyes also led to better BCVA and contrast sensitivity scores in the non-PCCC group because the IOLs would have contributed to worse mean BCVA and contrast sensitivity scores if included in the assessment before Nd:YAG treatment.
5.
6.
7.
Anterior Capsule Opacification The ACO intensity and pattern were equal in the PCCC group and non-PCCC group. Thus, performing a PCCC changes neither the intensity nor the pattern of ACO in eyes with hydrophilic acrylic IOLs with angulated haptics. Anterior capsule opacification was restricted to the capsulorhexis edge in both groups. This could be an effect of an initially floppy ACCC that is primarily in contact with the IOL but then detaches due to fibrotic shrinkage, leaving capsulorhexis edge–emphasized ACO with persisting anterior capsule gaping. The angulated haptics of the Corneal ACR6D SE IOL explain the more anterior capsule gaping and less ACO than in eyes with hydrophilic IOLs with a similar design but without angulated haptics.29 It has been suggested that a smaller ACCC induces more intense ACO by larger overlap of the anterior capsule and the IOL, which allows contact of more anterior LECs.30 It has also been suggested that a PCCC unbalances the contractile powers at the remaining posterior capsule, leading to more contraction and shrinkage of the ACCC and enlargement of the PCCC31 and eventually to haptic deformation29 or decentration of the IOL.31 However, the ACCC sizes at the follow-up in both groups in this study were equal; thus, in this study population, the PCCC seemed to have no influence on ACCC shrinkage and ACO.
8.
9.
10.
11. 12.
13.
14.
15.
16.
17. 18.
CONCLUSION Performing a PCCC significantly reduced PCO formation in the central 3.0 mm eccentricity and the need for Nd:YAG laser capsulotomy with the ACR6D SE single-piece hydrophilic acrylic IOL with angulated haptics.
19.
20.
REFERENCES 1. Nishi O, Nishi K. Preventive effect of a second-generation silicone intraocular lens on posterior capsule opacification. J Cataract Refract Surg 2002; 28:1236–1240 2. Kurosaka D, Yoshino M, Kurosaka H, Nakamuro K. Effect of posterior convexity of intraocular lenses on lens epithelial cell migration. Jpn J Ophthalmol 2003; 47:332–337 3. Nishi O, Nishi K, Sakanishi K. Inhibition of migrating lens epithelial cells at the capsular bend created by the rectangular optic edge of a posterior chamber intraocular lens. Ophthalmic Surg Lasers 1998; 29:587–594 4. Nishi O, Nishi K, Mano C, et al. The inhibition of lens epithelial cell migration by a discontinuous capsular bend created by
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a band-shaped circular loop or a capsule-bending tension ring. Ophthalmic Surg Lasers 1998; 29:119–125 Nishi O, Nishi K, Wickstro¨m K. Preventing lens epithelial cell migration using intraocular lenses with sharp rectangular edges. J Cataract Refract Surg 2000; 26:1543–1549 Nishi O, Nishi K. Preventing posterior capsule opacification by creating a discontinuous sharp bend in the capsule. J Cataract Refract Surg 1999; 25:521–526 Nishi O, Nishi K, Akura J, Nagata T. Effect of round-edged acrylic intraocular lenses on preventing posterior capsule opacification. J Cataract Refract Surg 2001; 27:608–613 Castaneda VE, Legler UFC, Tsai JC, et al. Posterior continuous curvilinear capsulorhexis; an experimental study with clinical applications. Ophthalmology 1992; 99:45–50 Gimbel HV, DeBroff BM. Posterior capsulorhexis with optic capture: maintaining a clear visual axis after pediatric cataract surgery. J Cataract Refract Surg 1994; 20:658–664 Koch DD, Kohnen T. Retrospective comparison of techniques to prevent secondary cataract formation after posterior chamber intraocular lens implantation in infants and children. J Cataract Refract Surg 1997; 23:657–663 Ellis FJ. Management of pediatric cataract and lens opacities. Curr Opin Ophthalmol 2002; 13:33–37 Raina UK, Mehta DK, Monga S, Arora R. Functional outcomes of acrylic intraocular lenses in paediatric cataract surgery. J Cataract Refract Surg 2004; 30:1082–1091 Kohnen T, Pen˜a-Cuesta R, Koch DD. Secondary cataract formation following intraocular lens implantation; 6-month results. Ger J Ophthalmol 1996; 5:171–175 Gimbel HV, Sun R, Ferensowicz M, et al. Intraoperative management of posterior capsule tears in phacoemulsification and intraocular lens implantation. Ophthalmology 2001; 108:2186– 2189; discussion by WJ Fishkind, 2190–2191 Tassignon M-J, De Groot V, Smets RME, et al. Secondary closure of posterior continuous curvilinear capsulorhexis. J Cataract Refract Surg 1996; 22:1200–1205 Tassignon M-J, De Groot V, Vervecken F, Van Tenten Y. Secondary closure of posterior continuous curvilinear capsulorhexis in normal eyes and eyes at risk for postoperative inflammation. J Cataract Refract Surg 1998; 24:1333–1338 Gimbel HV, DeBroff BM. Intraocular lens optic capture. J Cataract Refract Surg 2004; 30:200–206 Menapace R. Routine posterior optic buttonholing for eradication of posterior capsule opacification in adults; report of 500 consecutive cases. J Cataract Refract Surg 2006; 32:929–943; erratum, 1410 Georgopoulos M, Menapace R, Findl O, et al. After-cataract in adults with primary posterior capsulorhexis; comparison of hydrogel and silicone intraocular lenses with round edges after 2 years. J Cataract Refract Surg 2003; 29:955–960 Georgopoulos M, Menapace R, Findl O, et al. Prima¨re posteriore Kapsulorhexis: Einfluß der retrokapsula¨ren Viskoelastikumgabe auf den Augeninnendruckverlauf. In: Duncker F, Ohrloff C, Wilhelm F, eds, 12. Kongreß der Deutschsprachigen Gesellschaft fu¨r Intraokularlinsen-Implantation und refraktive Chirurgie, 1998. Berlin,Germany, Springer-Verlag, 1999; 59–63 Buehl W, Findl O, Menapace R, et al. Reproducibility of standardized retroillumination photography for quantification of posterior capsule opacification. J Cataract Refract Surg 2002; 28: 265–270 Findl O, Buehl W, Menapace R, et al. Comparison of 4 methods for quantifying posterior capsule opacification. J Cataract Refract Surg 2003; 29:106–111 Ginsburg AP. Contrast sensitivity and functional vision. Int Ophthalmol Clin 2003; 43(2):5–16
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24. Menapace R. Prevention of posterior capsule opacification. In: Kohnen T, Koch DD, eds, Cataract and Refractive Surgery; Essentials In Ophthalmology. Berlin, Germany, New York, NY, Springer, 2004; 101–122 25. Mu¨llner-Eidenbo¨ck A, Amon M, Schauersberger J, et al. Cellular reaction on the anterior surface of 4 types of intraocular lenses. J Cataract Refract Surg 2001; 27:734–740 26. Linnola RJ, Werner L, Pandey SK, et al. Adhesion of fibronectin, vitronectin, laminin, and collagen type IV to intraocular lens materials in pseudophakic human autopsy eyes. Part 1: histological sections. J Cataract Refract Surg 2000; 26: 1792–1806 27. Sugita M, Kato S, Sugita G, Oshika T. Migration of lens epithelial cells through haptic root of single-piece acrylic-foldable intraocular lens. Am J Ophthalmol 2004; 137:377–379 28. Heatley CJ, Spalton DJ, Kumar A, et al. Comparison of posterior capsule opacification rates between hydrophilic and hydrophobic single-piece acrylic intraocular lenses. J Cataract Refract Surg 2005; 31:718–724 29. Vock L, Menapace R, Stifter E, et al. Clinical effects of a primary posterior continuous curvilinear capsulorhexis in hydrophilic
acrylic single-piece intraocular lenses with and without haptic angulation. In Press, J Cataract Refract Surg 2007 30. Hayashi K, Hayashi H, Nakao F, Hayashi F. Reduction in the area of the anterior capsule opening after polymethylmethacrylate, silicone, and soft acrylic intraocular kens implantation. Am J Ophthalmol 1997; 123:441–447 31. Georgopoulos M, Menapace R, Findl O, et al. Posterior continuous curvilinear capsulorhexis with hydrogel and silicone intraocular lens implantation; development of capsulorhexis size and capsule opacification. J Cataract Refract Surg 2001; 27:825– 832
J CATARACT REFRACT SURG - VOL 33, APRIL 2007
First author: Lorenz Vock, MD, JD
Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses Lorenz Vock, MD, JD, Rupert Menapace, MD, Eva Stifter, MD, Wolf Bu¨hl, MD, Michael Georgopoulos, MD
PURPOSE: To evaluate the effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the clinical performance of a single-piece hydrophilic acrylic intraocular lens (IOL) with haptic angulation. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: A prospective study of 52 patients with bilateral age-related cataract was conducted. Patients had standard cataract surgery with implantation of the same IOL in both eyes. Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. Assessed parameters were visual axis opacification (VAO) in eyes with a PCCC or regeneratory posterior capsule opacification (PCO) in eyes without PCCC (scale 0 to 10) in the central (3.0 mm eccentricity), intermediate (3.0 to 4.5 mm eccentricity), and peripheral (>4.5 mm eccentricity [capsulorhexis edge]) areas; neodymium:YAG (Nd:YAG) laser capsulotomy or laser polishing of ongrowing lens epithelium; anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity. RESULTS: Thirty patients completed the 2½-year follow-up. Visual axis opacification was significantly lower in the central region in the PCCC group (mean 0.5 G 0.7 [SD]) than PCO in the central region of the non-PCCC group (mean 1.1 G 1.1) (P Z .02). Forty percent in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period; none in the PCCC group had laser polishing. There were no significant differences in ACO, SE, BCVA, or contrast sensitivity. There was no additional gain in BCVA or contrast sensitivity in eyes with a PCCC compared with eyes without a PCCC when VAO and PCO were low. CONCLUSION: A PCCC significantly reduced PCO formation within the central 3.0 mm eccentricity as well as the need for Nd:YAG laser capsulotomy in eyes with a single-piece hydrophilic acrylic IOL with angulated haptics. J Cataract Refract Surg 2007; 33:628–634 Q 2007 ASCRS and ESCRS
Currently, an effective way to prevent posterior capsule opacification (PCO) is to implant intraocular lenses (IOLs) with sharp posterior optic edges.1–7 However, the barrier effect of a sharp posterior optic edge may fail. In primary posterior curvilinear capsulorhexis (PCCC), the central part of the posterior capsule is removed during cataract surgery to prevent equatorial lens epithelial cell (LEC) migration onto the posterior capsule from reaching the visual axis. It was first recommended by Castaneda et al.8 and is frequently used to prevent more severe PCO formation in children’s eyes 9–11 in combination with 628
Q 2007 ASCRS and ESCRS Published by Elsevier Inc.
anterior vitrectomy or posterior optic capture.12,13 In adults, the PCCC technique is less frequently performed but is particularly useful in the management of intraoperative capsule tears.14 However, ongrowth of LECs over the PCCC rim onto the posterior surface of the IOL and secondary closure of the PCCC have been reported.15,16 Several methods of IOL optic capture to avoid secondary PCCC reclosure have been proposed.17,18 Georgopoulos et al.19 report that the benefit of a PCCC in reducing central PCO in adults is dependent on the IOL material because posterior ongrowth is found 0886-3350/07/$dsee front matter doi:10.1016/j.jcrs.2007.01.007
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629
Figure 1. Posterior capsule opacification evaluation areas. a: Peripheral, 4.5 mm (projected) margin of the ACCC eccentricity. b: Intermediate, 3.0 to 4.5 mm eccentricity. c: Central, 3.0 mm eccentricity.
more often on hydrogel IOL optics than on silicone optics. Little is known about the performance of a PCCC in eyes with IOLs with sharp optic edges and angulated haptics. Thus, we evaluated the effectiveness of a PCCC in eyes with a hydrophilic IOL with a sharp optic edge and 10-degree angulated haptics in a prospective randomized trial with an intrapatient design.
PATIENTS AND METHODS Fifty-two patients with bilateral age-related cataract were included in the trial. All had surgery in both eyes after exclusion for pseudoexfoliation syndrome, glaucoma, uveitis, and proliferative diabetic retinopathy. The trial was approved by the Ethics Committee of the Medical University of Vienna. All procedures were covered by the tenets of the Helsinki Declaration, and all patients provided informed consent.
Intraocular Lens The ACR6D SE (Laboratoires Corne´al) is a single-piece IOL of a hydrophilic acrylic copolymer of 2-hydroxyethyl methacrylate and ethyl methacrylate with a water content of 26%. It has an optic diameter of 6.0 mm and an overall length of 12.0 mm. The ACR6D SE IOL has 10-degree angulated haptics. The A-constant used with optical biometry was 120.
Accepted for publication January 3, 2007. From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. No author has a financial or proprietary interest in any material or method mentioned. Corresponding author: Rupert Menapace, MD, Department of Ophthalmology, Medical University of Vienna, Wa¨hringer Gu¨rtel 18-20, A-1090 Wien, Austria. E-mail: [email protected].
Surgical Technique All surgeries were performed in a standardized fashion by the same experienced surgeon (R.M.) using topical anesthesia and a 3.2 mm temporal self-sealing limbo-corneal tunnel incision. A well-centered, round, anterior continuous curvilinear capsulorhexis (ACCC) with a 5.0 mm diameter was aimed for to ensure appropriate overlap of the IOL optic. After hydrodissection and phacoemulsification were performed, a well-centered round PCCC with a diameter smaller than the ACCC was torn with a capsule forceps in the selected eye of the patient. The target diameter was 4.0 mm. The surgical technique used to ensure precise PCCC sizing has been described in detail.18 Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. An ophthalmic viscoelastic device (OVD) (hyaluronic acid 5000 10 mg/mL [Healon]) was used. Until the completion of cortex removal, the surgeon was unaware whether a PCCC would be made. After IOL implantation, the OVD was removed from the anterior chamber by irrigation/aspiration (I/A). In non-PCCC eyes, the retro-optical OVD was also aspirated by tilting up the optic and directly accessing the retrolental space with the coaxial I/A tip. In the PCCC eyes, the OVD was removed from the capsular bag periphery, but inherently not from behind the optic.20 Postoperative treatment consisted of prednisolone acetate (Ultracortenol) and diclofenac sodium (Voltaren) eyedrops 4 times a day for 4 weeks.
Image Analysis At the 2½-year follow-up, visual axis opacification (VAO), PCO, and the sizes of the ACCC and PCCC were assessed using digital retroilluminated photographs21 taken after maximum pupil dilation with a digital camera (NC2000, Kodak). The PCO and VAO were quantified using the Automated Quantification of After-Cataract (AQUA) system,22 which was developed in Vienna and defines 3 areas of evaluation (Figure 1).
Slitlamp Examination At 2½ years, the behavior of LECs at the PCCC rim was assessed at the slitlamp in eyes with a PCCC using the following categories: (1) free PCCC rim, (2) ruffled PCCC rim, and (3) posterior ongrowth (Figure 2). The number of neodymium:YAG (Nd:YAG) laser capsulotomies or Nd:YAG laser polishing of LEC ongrowth onto the optic surface
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Figure 2. Behavior of LECs at the PCCC. A: Free PCCC rim. B: Ruffled PCCC rim. C: Posterior ongrowth (arrows) PCCC rim. within the PCCC performed during the follow-up was recorded, and cases of buttonholing of the ACCC and PCCC were counted. Anterior capsule opacification (ACO) was assessed as being present (yes) or not present (no) and categorized by morphology as ACO of the capsulorhexis edge or ACO of the entire capsulorhexis leaf (ie, diffuse). Gaps between the anterior capsule leaf and the IOL optic (anterior capsule gaping) were subjectively categorized at the slitlamp as being present (yes) or not present (no). Best corrected visual acuity (BCVA) was assessed monocularly using a standard set of corrective lenses and Snellen charts under standardized conditions. Contrast sensitivity was tested using a standard Ginsburg box (VSCR-CST 1800) with a Functional Acuity Contrast Test (FACT) chart at 6 cd/m2 and at spatial frequencies of 1.5 to 18 cycles per degree (cpd). The last patch of the FACT chart the patient correctly identified before 2 consecutive errors was used to calculate the contrast sensitivity of that spatial frequency. The contrast sensitivity scores were transformed into logarithmic values for statistical analysis. A difference level of 0.15 logCSF23 (corresponding 1 patch in the chart) between the groups at a given spatial frequency was deemed clinically relevant.
Statistical Analysis Because of the intraindividual design of the study, paired tests were performed. Numeric and scaled data were analyzed using Friedmann and Wilcoxon tests. Paired categorized data were analyzed with McNemar chi-square tests and unpaired data, with standard chi-square tests. P values of proportions within the group with a PCCC were evaluated with the binomial distribution function. An a level of 0.05 was considered statistically significant. Eyes that had Nd:YAG treatment were excluded from the statistical analysis of
AFTER CATARACT [AQUA]
peripheral
intermediate
BCVA and contrast sensitivity. In the assessment of VAO and PCO, the central AQUA scores of Nd:YAG laser-treated eyes were estimated using the peripheral scores of the eyes.
RESULTS The mean patient age at surgery was 74 years G 10 (SD) (range 52 to 90 years). Thirty patients were available at the follow-up, 7 men (23%) and 23 women (77%). The mean follow-up was 2.4 G 0.4 years (range 1.6 to 3.7 years). Forty percent of eyes in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period, but no eye in the PCCC group had laser polishing. Visual axis opacification was significantly lower in the central region in the PCCC eyes than PCO in the central region in the non-PCCC eyes (Figure 3). No significant differences were found in ACO, anterior capsule gaping, or spherical equivalent (SE) or in BCVA or contrast sensitivity after exclusion of the eyes with Nd:YAG laser capsulotomy (Tables 1 and 2 and Figure 4). DISCUSSION In this prospective randomized trial, the impact of a PCCC on the clinical performance of a single-piece central p = 0.003
4.0
Figure 3. AQUA scores in eyes with and without PCCC in the central 3.0 mm eccentricity, intermediate 3.0 to 4.5 mm eccentricity, and peripheral 4.5 mm (projected) margin of the ACCC eccentricity (Figure 1) ( Z outliers; * Z extreme values).
2.0
0.0 PCCC no PCCC
PCCC no PCCC
PCCC no PCCC
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Table 1. Clinical parameters after 2½ years. Parameter VAO/PCO Central Mean G SD Median 95% CI Intermediate Mean G SD Median 95% CI Peripheral Mean G SD Median 95% CI Nd:YAG, n (%) Mean ACCC area (mm2) G SD Snellen BCVA (logMAR)* Mean G SD Median 95% CI CS (log)* 1.5 cpd Mean G SD Median 95% CI 3 cpd Mean G SD Median 95% CI 6 cpd Mean G SD Median 95% CI 12 cpd Mean G SD Median 95% CI 18 cpd Mean G SD Median 95% CI ACO, n (%) ACO pattern, n (%) Capsulorhexis edge Diffuse ACG SE (D) Mean G SD Median 95% CI
No PCCC
PCCC
1.1 G 1.1 0.9 0.6 to 1.5
0.5 G 0.7 0.2 0.2 to 0.7
1.4 G 0.9 1.1 1.1 to 1.7 1.5 G 0.9 1.3 1.1 to 1.8
1.4 G 0.9 1.2 1.1 to 1.8
12 (40) 16.0 G 3.0
1.7 G 0.9 1.7 1.3 to 2.0 0 16.2 G 3.2
0.10 G 0.11 0.10 0.17 to 0.03
0.10 G 0.13 0.12 0.16 to 0.05
n
P Value
29
.003
29
.83
29
.39
30 30 14/26
!.0001 .8 .96
17/26 .61 1.41 G 0.22 1.55 1.29 to 1.52
1.49 G 0.23 1.55 1.40 to 1.59
1.27 G 0.63 1.46 0.94 to 1.59
1.47 G 0.60 1.67 1.22 to 1.71
1.11 G 0.77 1.36 0.72 to 1.51
1.35 G 0.63 1.58 1.09 to 1.60
0.38 G 0.55 0.0 0.1 to 0.66
0.65 G 0.64 0.90 0.39 to 0.91
0.11 G 0.26 0.0 0.1 to 0.25 17 (57)
0.26 G 0.44 0.0 0.08 to 0.44 14 (47)
.28
.87
.19
.09
11 (37) 4 (13) 24 (80) 0.99 G 1.02 1.0 1.38 to 0.59
11 (37) 3 (10) 25 (83)
30 30
.43 .92
30 28
0.74 0.85
1.04 G 1.08 0.93 1.46 to 0.62
ACCC Z anterior continuous curvilinear capsulorhexis; ACG Z anterior capsule gaping; ACO Z anterior capsule opacification; BCVA Z best corrected visual acuity; CI Z confidence interval; cpd Z cycles per degree; CS Z contrast sensitivity function; PCCC Z primary posterior continuous capsulorhexis, PCO Z posterior capsule opacification; Nd:YAG Z neodymium:YAG capsulotomy; SE Z spherical equivalent; VAO Z visual axis opacification *Nd:YAG treated eyes excluded
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without a PCCC (0.6 AQUA units) (P Z .003) when a hydrophilic IOL with sharp optic edges and 10-degree angulated haptics was implanted. In both groups, PCO in the peripheral and intermediate areas remained equally high and was not significantly different. In the intermediate area in the PCCC eyes, LECs accumulated around the PCCC rim and posterior ongrowth occurred, which were responsible for higher AQUA scores than in the central region. In the non-PCCC eyes, high PCO scores in the intermediate area were the result of the normal migration of LECs onto the posterior capsule. The number of Nd:YAG laser capsulotomies was high in the nonPCCC group; thus, the effect of the sharp optic edge of the hydrophilic acrylic IOL with haptic angulation and broad haptic junctions was insufficient to prevent vision-disturbing PCO in two fifths of the cases. Despite the hydrophilic material, the presence of a PCCC could have significantly reduced central VAO in the PCCC group. Still, many cases of ruffled PCCC rims and posterior ongrowth were seen, which presumably are linked to the good biocompatibility of the hydrophilic material with regard to LECs. Further follow-up is necessary determine whether IOLs with a ruffled PCCC rim develop posterior ongrowth later.
Table 2. Behavior of LECs at the PCCC rim. Parameter
Yes
No
N
P Value
Free rim Ruffled rim Posterior ongrowth
17 10 3
13 20 27
30 d d
.58 .09 .000008
hydrophilic acrylic IOL with a sharp posterior edge (ACR6D SE) was evaluated. It was shown that in eyes with this type of IOL, a PCCC significantly reduced central PCO as well as the need for Nd:YAG treatment. Eyes with a PCCC required no Nd:YAG capsule polishing, while 40% of without a PCCC required Nd:YAG laser capsulotomy. Visual Axis and Posterior Capsule Opacification and Neodymium:YAG Treatment The development of PCO is dependent on many factors24 including the IOL optic edge,1–7 material,25,26 or haptic junction.27,28 In particular, with single-piece IOLs, the barrier effect of the sharp optic edge is often reduced at broad haptic junctions, allowing ongrowth of LECs onto the posterior capsule.26 Material properties of IOLs also seem to influence the performance of a PCCC; Georgopoulos et al.19 found less posterior ongrowth with silicone IOLs than with hydrogel IOLs, both of which have open-loop haptics and do not have sharp posterior edges. Little, however, is known about the effects of a PCCC in eyes with IOLs with sharp optic edges and angulated haptics. In our study, the presence of a PCCC significantly reduced central VAO compared with PCO in eyes 1.5 cpd
3 cpd
6 cpd
°
2.00
CSF [log]
Best Corrected Visual Acuity and Contrast Sensitivity Neither BCVA nor contrast sensitivity were significantly different between the PCCC group and the non-PCCC group. This result is biased by the high number of Nd:YAG treatments in the non-PCCC group. As Nd:YAG treatment by nature restores BCVA and contrast sensitivity in eyes with previously high PCO,
°
1.50 °
1.00
Figure 4. Contrast sensitivity function (cpd) ( Z outliers; * Z extreme values).
0.50 0.00 PCCC
no PCCC
PCCC
no PCCC
*
*
PCCC
no PCCC
18 cpd
12 cpd
CSF [log]
2.00 1.50
°
1.00 * *
0.50 0.00 PCCC
no PCCC
PCCC
no PCCC
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these eyes had to be excluded from assessment. But excluding Nd:YAG-treated eyes also led to better BCVA and contrast sensitivity scores in the non-PCCC group because the IOLs would have contributed to worse mean BCVA and contrast sensitivity scores if included in the assessment before Nd:YAG treatment.
5.
6.
7.
Anterior Capsule Opacification The ACO intensity and pattern were equal in the PCCC group and non-PCCC group. Thus, performing a PCCC changes neither the intensity nor the pattern of ACO in eyes with hydrophilic acrylic IOLs with angulated haptics. Anterior capsule opacification was restricted to the capsulorhexis edge in both groups. This could be an effect of an initially floppy ACCC that is primarily in contact with the IOL but then detaches due to fibrotic shrinkage, leaving capsulorhexis edge–emphasized ACO with persisting anterior capsule gaping. The angulated haptics of the Corneal ACR6D SE IOL explain the more anterior capsule gaping and less ACO than in eyes with hydrophilic IOLs with a similar design but without angulated haptics.29 It has been suggested that a smaller ACCC induces more intense ACO by larger overlap of the anterior capsule and the IOL, which allows contact of more anterior LECs.30 It has also been suggested that a PCCC unbalances the contractile powers at the remaining posterior capsule, leading to more contraction and shrinkage of the ACCC and enlargement of the PCCC31 and eventually to haptic deformation29 or decentration of the IOL.31 However, the ACCC sizes at the follow-up in both groups in this study were equal; thus, in this study population, the PCCC seemed to have no influence on ACCC shrinkage and ACO.
8.
9.
10.
11. 12.
13.
14.
15.
16.
17. 18.
CONCLUSION Performing a PCCC significantly reduced PCO formation in the central 3.0 mm eccentricity and the need for Nd:YAG laser capsulotomy with the ACR6D SE single-piece hydrophilic acrylic IOL with angulated haptics.
19.
20.
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First author: Lorenz Vock, MD, JD