In vivo digital imaging of the square-edged barrier effect of a silicone intraocular lens.J Cataract Refract Surg. 2004 Dec; 30(12):2574-84.JC
To evaluate and compare by high-magnification digital photography the lens epithelial cell (LEC) response and capsule dynamics in vivo after implantation of a square-edged and a round-edged silicone intraocular lens (IOL) in a fellow-eye study.
Private practice and Royal Victoria Hospital, Barrie, and Soldiers' Memorial Hospital, Orillia, Ontario, Canada.
After phacoemulsification, a single surgeon implanted a square-edged silicone IOL (SoFlex SE, Bausch & Lomb) in 25 patients who had previously had a conventional round-edged version of the same IOL (SoFlex Li61U, Bausch & Lomb) implanted in their contralateral eye within a 6-week period. SoFlex SE IOL recipients were selected sequentially from those scheduled for surgery within a 3-day period. The IOLs were sequentially photographed 1 week and 1, 3, 6, and 9 months after surgery using magnification of at least x64 through a biomicroscope and a high-resolution digital camera with adapter. Images were transferred to a graphics computer and compared over time.
At 1 week, both designs had evidence of LEC migration along the posterior capsule, with the highest cell density around the 6 o'clock position. At 1 month, both IOL designs showed 360 degrees of anterior and posterior capsule adhesion to the edge of the optic. At 1 month, however, migrating LECs encountered a "damming" effect at the square posterior edge but not at the round edge. A thin fibrotic ring began to form around the SoFlex SE edge at 2 months and was complete for 360 degrees at 3 months. At 9 months, there was no evidence of LEC migration beyond this ring. With round-edged IOLs, the fibrotic ring never fully formed and LEC migration continued posterior to the optic. There was a tight capsule shrink-wrap effect with the square-edged IOLs with the fibrotic ring, allowing minimal IOL movement between 1 month and 9 months. The round-edged IOLs tended to decenter and rotate. Anterior capsulorhexis contraction was greater at every time point with the round-edged IOLs than with the square-edged IOLs.
Early contact inhibition of LECs by a square-edged IOL design and its effects were demonstrated in vivo with sequential, high-resolution digital photography and commercially available graphics software.