R 637
Eradication of posterior capsule opacification (pco)
D. J. Apple
We report the Nd:YAG laser posterior capsulotomy rate (%) of 8 intraocular lens (IOL) designs in a prospective analysis series of 5,416 pseudophakic human eyes obtained postmortem, accessioned in our Center between January 1988 and January 2000. We identify factors that are instrumental in reducing the incidence of PCO/Nd:YAG laser posterior capsulotomy. The following posterior chamber (PC)-IOL styles were analyzed in this study: rigid 3-piece PMMA, rigid 1-piece PMMA, foldable 3-piece silicone, 3-piece acrylic, (the Alcon AcroSofä lens), foldable 1-piece silicone-plate IOL, small hole design, foldable 3-piece silicone optic-polyimide haptic design, foldable 1-piece silicone-plate IOL, large hole design, and a foldable 3-piece silicone optic-PMMA haptic design, (the Allergan SI40). Each formalin fixated globe was sectioned in the equatorial plane and analyzed using the Miyake-Apple posterior photographic technique.
The Nd:YAG laser posterior capsulotomy rate (%) as of January 2000 was documented. In addition, the Nd:YAG laser posterior capsulotomy rate for each lens was plotted on a monthly basis for the same period, creating a computerized trend or "time line" for each IOL style. Higher Nd:YAG laser posterior capsulotomy rates ranging from 20.3-33.4% were noted with four relatively older designs (up to mid-1990s). These included two foldable designs and the two rigid designs, 1 and 3-piece lenses with PMMA optics. Four modern foldable IOLs manufactured from silicone and acrylic materials that had Nd:YAG laser posterior capsulotomy rates ranging from 0.9% (Alcon AcrySofä ) to 17.1%. The difference concerning the YAG rates among the 8 groups of lenses was found to be significant (P < 0.0001, Chi-squared test). Comparing foldable versus rigid designs, it was found that the foldable lenses were associated with a much lower Nd:YAG laser posterior capsulotomy rate (14.1% vs. 31.1%).
Utilizing the six factors regarding surgical technique and IOL choice described in this paper, we strongly believe that the overall incidence of PCO and incidence of Nd:YAG laser posterior capsulotomy is now decreasing from as high as 50% in the 1980s-early 1990s to single digits. The tools are available, careful application and utilization of these by surgeons can genuinely lead to a direction towards eradication of secondary cataract, the second most common cause of visual loss worldwide.
Department of Ophthalmology, Storm Eye Institute, Charleston, South Carolina