Posterior Capsule Opacification in 5.5 mm Versus 6.0 mm AcrySof Lenses
We appreciate Dr. Bhartiya's interest in our paper. In this study, we found there was less PCO with 6.0 mm optic AcrySof lenses than with 5.5 mm optic lenses (6.9% coverage of the posterior capsule versus 1.5% coverage at 1 year). We speculated on the reason for this finding. It might be simply that the 6.0 mm optic produces a more peripheral barrier to lens epithelial cell growth. An alternative explanation might be that the haptics on the 6.0 mm lens are more angulated and therefore could conceivably push the optic back more firmly onto the posterior capsule. This could effectively increase the pressure between the optic edge and the posterior capsule, producing a physical barrier to lens epithelial cell growth at the square optic edge.
Dr. Bhartiya suggests that one could test this hypothesis by taking a 13.0 mm diameter haptic with either a 6.0 mm or 5.5 mm optic. The 5.5 mm optic AcrySof IOL is, of course, manufactured with a 12.5 mm diameter haptic so this would not be possible, but in any case, it would be geometrically impossible for both IOLs to have the same angulation as the lens bag diameter is constant.
Although we found less PCO with the 6.0 mm optic AcrySof lens at 1 year (4.5% at 3 months versus 1.5% at 1 year), this may not be statistically significant. It is interesting to note, however, that lens epithelial cell growth with AcrySof lenses can regress over time. 1,2
David J. Spalton FRCP, FRCS, FRCOphth
1. Hollick EJ, Spalton DJ, Ursell PG, Pande MV. Lens epithelial cell regression on the posterior capsule with different intraocular lens materials. Br J Ophthalmol 1998; 82:1182-1188
© 2002 by Lippincott Williams & Wilkins, Inc.
2. Meacock WR, Spalton DJ, Hollick ER, et al. The effect of polymethylmethacrylate and AcrySof lenses on posterior capsule in patients with a large capsulorhexis. Jpn J Ophthalmol 2001; 45:348-354