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

  Correspondence to:

  Seyed-Farzad Mohammadi, MD

  Eye Research Center , Farabi Eye Hospital , Tehran

  Tel: +98 21 55414941-6

  Email: sfmohamm@razi.tums.ac.ir

References

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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 Oct;136(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 Oct;111(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 Apr;113(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 Jun;88(6):746-9.