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DISCUSSION

Short axial length and shallow anterior chamber eyes have higher incidence of complications in the surgery of phacoemulsification[1,2]. Successful CCC is very important to maintain the integrity of capsule bag and reduce the complications.In the procedure of CCC, the capsulorhexis edge is exerted upon by the force upright, which originates from vitreous pressure transmitted by lens content and cortex swelling afer absorbing aqueous humor. The force can be separated into two component forces. One is directed vertical to the anterior capsule, the other is tangent to the anterior capsule. In routine CCC the tangent force is directed to the periphery of lens. If viscoelastic agent can¬ðt counteract the force tangent to the anterior capsule surface, the tangent force will cause the capsulorhexis edge to tear peripherally. In controlled CCC, the tangent force is directed to the center of lens because of the foveation of the anterior lens capsule and will not lead to the capsulorhexis edge tearing peripherally. (Figure 1 and Figure 2). In short axial length and shallow anterior chamber eyes, especially in those with glaucoma, vitrous pressure is higher than that in normal eye.Increased intravitreal pressure and decreased anterior chamber depth will lead to high pressure on tearing spot[6]. Filling the anterior chamber with viscoelastic agent usually can¬ðt counteract the force exerted on the anterior capsule originating from vitrous pressure and cortex swelling. The technique of controlled CCC can decrease the amount and change the direction of the force exerted upon the capsulorhexis edge. The capsulorhexis becomes more controllable and its success rate increases greatly compared with the routine CCC technique. Furthmore, the controlled CCC technique can be applied to cataract with or without liquefied cortex. It¬ðs applicable to a wider range of cases than some technique of aspirating liquid cortex before CCC to make the capsulorhexis controllable. Of course precaution should be taken that anterior lens surface be pressed properly to avoid zonular fibers injury.

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1 Webster R, Sassani J, Shenk R, Harris M, Gerber J, Benson A, Blumenstock J, Billman C, Haluck R. Simulating the continuous curvilinear capsulorhexis procedure during cataract surgery on the EYESI system. Stud Health Technol Inform2005;111:592ª²595

2 Rao SK, Padmanabhan P. Capsulorhexis in eyes with phacomorphic glaucoma. J Cataract Refract Surg1998;24(7):882ª²884

3 Spencer MH. Direct puncture capsulorhexis. J Cataract Refract Surg 2005;31(8):1490ª²1492

4 Chan DD, Ng AC, Leung CK, Tse RK. Continuous curvilinear capsulorhexis in intumescent or hypermature cataract with liquefied cortex. J Cataract Refract Surg2003;29(3):431ª²434 Ò½.ѧ.È«.ÔÚ.Ïßwww.lindalemus.com

5 Bhattacharjee K, Bhattacharjee H, Goswami BJ, Sarma P. Capsulorhexis in intumescent cataract. J Cataract Refract Surg1999;25(8):1045ª²1047

6 Mohammad Taher Rajabi, Ali Sadeghi Tari, Mohmoud Jabbarvand, Mohammad Bagher Rajabi. A reappraisal of the Capsulorhexis: Tearing angle in capsulorhexis. Int J Ophthalmol(Guoji Yanke Zazhi)2007;7(2): 315ª²318

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