In a fellow-eye-controlled trial, we compared the posterior capsule opacification (PCO) rates of single-piece (SA60AT) and three-piece (MA60AC) hydrophobic acrylic intraocular lenses (IOL) in 54 pair-matched eyes of 27 age-related cataract patients who consecutively underwent bilateral (4-8 weeks apart) phacoemulsification horizontal chopping performed through a capsulorrhexis of approximately 5- 5.5 mm in diameter followed by in the bag fixation of the IOL. PCO grading was done according to Evaluation of Posterior Capsule Opacification (EPCO) system1 by two independent observers.
At last follow up (mean: 6 months), 42.5, 42.5, 13, and 2% of the eyes had a PCO scores of 0, 1, 2, and 3, respectively and eyes with a single-piece IOL were tended to have higher PCO grades (odds ratio for a PCO grade of 1 or more: 2.9 P=0.08). PCO showed significant progression during the follow up (P<0.004). Last follow up m eans of best-corrected visual acuity (BCVA) were comparable (P=0.857). Despite significant progression of PCO, mean BCVA of month one and last follow ups were also comparable (P=0.859). Mean follow up for the two groups of eyes was comparable (P=0.396).
Wallin et al2 demonstrated that there was a significantly more severe PCO with the SA30AL single-piece compared with the MA30BA three-piece IOL with two years of follow up. Sacu et al3 reported that the single-piece (SA30AL and SA60AT) IOLs showed slightly more severe PCO than the three-piece (MA30BA and MA60BA) IOLs at one year postoperatively. However, two years postoperatively PCO intensity was comparable.3 In a recent study, Nejima et al4 failed to show a significant difference in the degree of PCO between the IOL types evaluated in the current study at one year. In another study,5 they found no significant difference between SA30AL and MA30BA IOLs PCO severity at one year postoperatively. Bender et al6 also observed a similar percentage area of PCO for SA30AL single-piece and MA30BA three-piece IOLs at six months and one year postoperatively.
In conclusion, single-piece hydrophobic acrylic IOLs may be associated by a higher PCO rates than the three-piece counterpart in short term but the difference is not of a remarkable clinical significance. Long term PCO rates seem comparable.
Mohammad-Ali Zare, MD Assistant Prof. of Ophthalmology*
Helia Heidari , MD Resident in Ophthalmology*
Hassan Hashemi, MD Associate Prof. of Ophthalmology*
S-Farzad Mohammadi, MD Fellowship in Cornea*
* Eye Research Center , Farabi Eye Hospital ,
Medical Sciences/University of Tehran
Seyed-Farzad Mohammadi, MD
Eye Research Center , Farabi Eye Hospital , Tehran
Tel: +98 21 55414941-6
1. Findl O, Buehl W, Menapace R, Georgopoulos M, Rainer G, Siegl H, Kaider A, Pinz A. Comparison of 4 methods for quantifying posterior capsule opacification. J Cataract Refract Surg. 2003 Jan29(1):106-11.
2. Wallin TR, Hinckley M, Nilson C, Olson RJ. A clinical comparison of single-piece and three-piece truncated hydrophobic acrylic intraocular lenses. Am J Ophthalmol. 2003 Oct136(4):614-9.
3. Sacu S, Findl O, Menapace R, Buehl W, Wirtitsch M. Comparison of posterior capsule opacification between the 1-piece and 3-piece Acrysof intraocular lenses: two-year results of a randomized trial. Ophthalmology. 2004 Oct111(10):1840-6.
4. Nejima R, Miyai T, Kataoka Y, Miyata K, Honbou M, Tokunaga T, Kawana K, Kiuchi T, Oshika T. Prospective intrapatient comparison of 6.0-millimeter optic single-piece and 3-piece hydrophobic acrylic foldable intraocular lenses. Ophthalmology. 2006 Apr113(4):585-90.
5. Nejima R, Miyata K, Honbou M, Tokunaga T, Tanabe T, Sato M, Oshika T. A prospective, randomised comparison of single and three piece acrylic foldable intraocular lenses. Br J Ophthalmol. 2004 Jun88(6):746-9. Bender LE, Nimsgern C, Jose R, Jayaram H, Spalton DJ, Tetz MR, Packard RB, Meacock W, Boyce J. Effect of 1-piece and 3-piece AcrySof intraocular lenses on the development of posterior capsule opacification after cataract surgery. J Cataract Refract Surg. 2004 Apr30(4):786-9.