Abstract
Abstract: :
Purpose: Posterior capsule «plaques»,or residual capsule opacity (RCO), at the time of surgery have been noted since the advent of ECCE. It is unknown to what extent an RCO noted intra-operatively contributes later to a visually significant posterior capsule opacity (PCO). We performed a prospective study to evaluate the incidence, to develop a classification, and to propose the possible management of such RCOs. Methods: 196 cataract surgeries were evaluated between July 2000 and July 2001. Pre-operative lens exam was noted as mature or immature. The immature cataracts were graded for nuclear sclerosis (NS), posterior subcapsular cataract (PSC), and anterior cortical spokes (ACS) on a 1 to 4 scale. Pre-operative Snellen best-corrected visual acuities were noted and converted to logMAR scale. The posterior capsule at the end of cataract surgery was classified as either clear or with RCO despite polishing the posterior capsule. Those with RCOs were further classified as either a plaque, a band, multiple punctate lesions, many fine fibers, or as having capsular folds. It was also noted whether these were centrally located (within the central 4mm) or peripheral. Those with RCOs were then followed to evaluate for the presence of a visually significant PCO at the sixth week post-operative examination. Results: The overall incidence of RCO was 23.5 % (46 eyes). 58.7% of these RCOs were central. The majority of RCOs were plaque at 58.7%. The mean preoperative logMAR acuity +/- SD in the RCO group was -1.27 +/- 0.61 as compared to -0.79 +/- 0.51 in the clear group (p<0.0001). Of the 14 mature cataracts in the study, 57.1% (8) had RCO. In contrast, of the 182 immature cataracts, 20.9% (38 eyes) had RCO (p=0.005). In the immature cataracts, the amount of PSC and NS are independent, statistically significant risk factors for RCO using stepwise logistic regression analysis. These risks are multiplicative. The adjusted odds ratio for each grade of NS was 2.29 and PSC was 1.83 (p= 0.002, p<0.001 respectively). 10.6 % of RCOs (5 eyes) resulted in a visually significant PCO at the sixth week post-operative exam. All 5 of these RCOs were noted to be central at the time of the surgery. Conclusions: Those patients who had an RCO at the time of surgery had a 10.6% chance of developing a visually significant PCO. Risk factors for an RCO include severe PSC and NS. Likewise, mature cataracts have a higher incidence of RCO. Although surgeons should polish the posterior capsule, aggressive polishing of peripheral RCOs is not advised.
Keywords: 522 posterior capsular opacification (PCO) • 338 cataract