As pointed out in the letter by Fan et al., the study published in 20031 includes different IOLs than those used in the recent study. The main outcome measure in the earlier study was to elucidate the impact of different IOL materials—a hydrophobic acrylic versus a hydrophobic silicone—on the development of posterior optic ongrowth of LECs. Looped IOLs of comparable design were used. The 2003 study demonstrated that silicone optics led to significantly lower rates of posterior optic ongrowth and reclosure of the PCCC. The significantly higher overall rates in the recent study are mainly explained by the difference in the optic edge design: round-edged in the 2003 study and sharp-edged in the recent study. With a greater number of LECs overcoming the round optic edge and populating the residual peripheral posterior capsule, the possibility of ongrowth onto and reclosure of the PCCC opening will also increase.
Moreover, the IOL material might play a role. Tognetto et al.2 found that the hydrophilic materials in our 2 studies differ in their propensity for LEC ongrowth because of differences in their biocompatibility. Differences in haptic design are another factor. In fact, the main outcome measure of the recent study was to establish the influence of haptic angulation (angulated with the ACR6D SE and nonangulated with the C-flex 570C) by using IOLs with otherwise comparable design: 1-piece hydrophilic with fenestrated flange-loop haptics.
Fan et al. proposed that a control group be used to elucidate the effect of the PCCC itself. Actually, we recently published the results of PCCC versus in-the-bag implantation using the ACR6D SE hydrophilic acrylic IOL with angulated haptics.3 In that study, visual axis opacification was significantly lower in the PCCC group than in the non-PCCC group.
Regarding the complication profile of the PCCC itself, there is widespread hesitation about the routine use of a PCCC because of concern about intraoperative and postoperative complications. Following the surgical guidelines, which have been described,4 a PCCC can be safely performed under topical anesthesia without running the risk for vitreous presentation in the anterior chamber. In a retrospective study by Van Cauwenberge et al.,5 performing a PCCC did not increase the risk for RD or CME. In a recent series of 500 consecutive PCCC cases combined with optic buttonholing,4 Menapace found only 1 case of delayed (4 months postoperatively) localized peripheral RD emerging from a group of small round holes in the highly myopic eye of a young man. With this risk profile and an intact anterior hyaloid surface, it seems unlikely that this complication was due to the PCCC procedure. In a number of prospective randomized trials to follow, Stifter and Menapace et al. specifically investigated the effect of adding a PCCC combined with posterior optic buttonholing on intraocular pressure,6 flare,7 and the thickness and morphology of the macula shown by optical coherence imaging in pertinent intraindividual comparison studies (R. Menapace, MD, E. Stifter, MD, “Macular Thickness and Morphology Following Cataract Surgery with Posterior Capsulorhexis and Optic Buttonholing,” presented at the XXV Congress of the European Society of Cataract and Refractive Surgeons, Stockholm, Sweden, September 2007). There was no difference between the group with PCCC and the group with standard in-the-bag placement in any of these parameters, nor was there a difference between the patients with an intact anterior hyaloid surface and a subgroup of patients with a punctured anterior hyaloid surface. In one of the comparative trials mentioned above, a patient developed a delayed RD in the non-PCCC eye. When buttonholed posteriorly into a PCCC, the optics remain in a stable posterior position, whereas there is an axial anterior optic shift with angulated IOLs placed in the bag (E. Stifter, MD, R. Menapace, MD, “Postoperative Anterior Chamber Depth and Posterior Chamber Lens Position Following Cataract Surgery with Posterior Capsulorhexis and Optic Buttonholing,” presented at the 21 Kongreß der Deutschsprachigen Gesellschaft für Intraokularlinsen-Implantation und refraktive Chirurgie, Potsdam, Germany, March 2007). The lack of anterior shift may prevent anterior movement of the vitreous body and thus counteract posterior vitreous detachment as a source of RD. It therefore appears that PCCC is a safe procedure that does not increase the incidence of retinal complications.
We welcome Fan et al.'s suggestion for a risk–benefit assessment of performing a PCCC in adult eyes. It seems clear that such an assessment will be multifactorial, depending on the design and material of the IOL among other factors. However, we believe that performing a PCCC with or without adjunctive surgical techniques, such as posterior optic buttonholing to reduce PCO,4 may become more widespread in the future. We believe that in addition to current findings, the speed of capsule fusion described by Nishi et al.8 is only one important factor of LEC migration early postoperatively. A delayed progressive failure of the barrier formed by the sharp optic edges becomes obvious 3 to 5 years postoperatively, leading to a high rate of Nd:YAG laser capsulotomies (W. Bühl, MD, et al., “Effect of Optic Material on Posterior Capsule Opacification in Intraocular Lenses with Sharp Edge Optics,” presented at the joint meeting of the European Society of Ophthalmology and the American Academy of Ophthalmology, Vienna, Austria, June 2007). In our own retrospective study, capsulotomy rates at 10 years with a hydrophobic acrylic IOL with sharp posterior edges were as high as 42% (L. Vock, MD, et al., “PCO Preventive Effect of Sharp-edged Hydrophobic Acrylic IOLs and Round-edged Silicone IOLs 10 Years After Surgery,” presented at the XXV Congress of the European Society of Cataract and Refractive Surgeons, Stockholm, Sweden, September 2007).
Posterior continuous curvilinear capsulorhexis as an adjunctive procedure is effective and safe if appropriately performed by experienced surgeons. One-piece IOLs with fenestrated flange-loop haptics should not be used because of possible haptic distortion, which might result in optic tilt and decentration.
1. 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.
2. Tognetto D, Toto L, Ballone E, Ravalico G. Biocompatibility of hydrophilic intraocular lenses. J Cataract Refract Surg. 2002;28:644-651.
3. Vock L, Menapace R, Stifter E, et al. Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses. J Cataract Refract Surg. 2007;33:628-634.
4. 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.
5. Van Cauwenberge F, Rakic J-M, Galand A. Complicated posterior capsulorhexis: aetiology, management, and outcome. Br J Ophthalmol. 1997;81:195-198.
6. Stifter E, Luksch A, Menapace R. Postoperative course of intraocular pressure after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing. J Cataract Refract Surg. 2007;33:1585-1590.
7. Stifter E, Menapace R, Luksch A, et al. Objective assessment of intraocular flare after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing in adults. In press. Br J Ophthalmol 2007. Abstract available at:http://bjo.bmj.com/cgi/content/abstract/bjo.2007.120535v1
. Accessed June 26, 2007.
8. Nishi O, Nishi K, Akura J. Speed of capsular bend formation at the optic edge of acrylic, silicone, and poly(methyl methacrylate) lenses. J Cataract Refract Surg. 2002;28:431-437.