Short-term changes in the morphology of posterior capsule opacification Wolf Buehl, MD, Oliver Findl, MD, Thomas Neumayer, MD, Michael Georgopoulos, MD, Stefan Sacu, MD Purpose: To observe and document posterior capsule opacification (PCO) growth in vivo over a short period of time (4 weeks). Setting: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. Methods: Fifteen eyes of pseudophakic patients with PCO of varying degrees were included in this prospective study. Digital retroillumination images were taken in a standardized fashion at 3 time points: 1 baseline image, a second image after 2 weeks, and a third image after 4 weeks. Thus, a 3-image series could be created for each eye. Additionally, sections of the posterior capsule with interesting structures were photographed with higher magnification and compared in supplementary image series. Morphologic changes in the PCO structure (eg, number and size of Elschnig pearls, total PCO area) were analyzed in the image series. Results: In all cases, significant changes could be observed between the 3 time points. In 71% of cases, some Elschnig pearls increased in size during the first 2 weeks and during weeks 3 and 4. In 73% of cases, however, there was a reduction a pearl size or even disappearance of some Elschnig pearls. The total PCO area did not change significantly during the 4-week period. Conclusions: Development of (regeneratory) PCO is a very dynamic process that includes not only growth of preexisting structures and occurrence of new Elschnig pearls, but also reorganization and even disappearance of pearls within a short time period (2–4 weeks). The latter in particular is not well known but could be observed in the majority of cases in this study. J Cataract Refract Surg 2005; 31:962–968 ª 2005 ASCRS and ESCRS A fter-cataract, or posterior capsule opacification (PCO), remains the most common long-term complication of modern cataract surgery. 1,2 The in- cidence of PCO strongly depends on the type of intraocular lens (IOL) and other factors; published PCO rates differ considerably among authors. 3 A variety of studies has led to a better understanding of the pathogenesis of PCO, and various approaches have been developed to reduce or to prevent the formation of PCO. Nonetheless, it is still not fully understood why some eyes develop PCO while the posterior capsules in other eyes remain completely clear. After-cataract has 2 clinical presentations, regener- atory and fibrotic. Regeneratory PCO is more common and is the main reason for a decrease in visual function after implantation of an IOL. It is caused by residual equatorial lens epithelial cells (LEC) that migrate and proliferate between the posterior capsule and the IOL, forming monolayers and later (Elschnig) pearls, leading to a decrease in visual acuity and loss of contrast sensitivity. Several studies have investigated PCO growth and speed and the influencing factors. 4–9 Most of these studies use an overall PCO score that incorporates PCO area, density, or both and is estimated during slitlamp examination or calculated with dedicated software systems using digital retroillumination or Scheimpflug images. 10 This is an adequate method for clinical trials of PCO preventative factors. However, the time interval between follow-up examinations of most longitudinal Ó 2005 ASCRS and ESCRS 0886-3350/05/$-see front matter Published by Elsevier Inc. doi:10.1016/j.jcrs.2004.08.051