IN-VIVO QUANTITATIVE MEASUREMENT OF POSTERIOR CAPSULE OPACIFICATION AFTER EXTRACAPSULAR CATARACT-SURGERY

PURPOSE: To introduce a new in vivo quantitative measurement of poster ior capsule opacification (PCO) after extracapsular cataract surgery a nd also to analyze the correlation between opacification density and t he patient's visual acuity. METHODS: Prospectively, the opacification density value in the central 3-mm portion of the posterior capsule was quantitated by means of an area densitometry with the Scheimpflug pho tography system (EAS-1000). The EAS-1000 examination was performed on 40 eyes with clinically significant PCO both before and after undergoi ng Nd:YAG laser posterior capsulotomy, and on 10 eyes without PCO. The correlation between the opacification density value and the visual ac uity was analyzed with a linear regression analysis. RESULTS: The mean opacification density values +/- SD were 48.8 +/- 29.5 computer-compa tible tapes (CCT) steps in the PCO group before capsulotomy, 15.5 +/- 7.8 CCT steps in the PCO group after capsulotomy, and 12.9 +/- 4.9 CCT steps in the non-PCO group. The mean opacification density value in t he PCO group before capsulotomy was significantly greater than that in the PCO group after capsulotomy or than that of the non-PCO group. A linear regression analysis determined that the opacification density v alue also correlated well with the visual acuity (R-2 = .808). CONCLUS IONS: We have established a new in vivo quantitative measurement of PC O. Because the opacification density value obtained by this measuremen t correlated well with the patient's visual acuity, we consider this m easurement to be useful in both the research and clinical management o f PCO. (C) 1998 by Elsevier Science Inc. All rights reserved.).