Decreasing rate of capsule complications in cataract surgery Eight-year study of incidence, risk factors, and data validity by the Swedish National Cataract Register

PURPOSE: To define the incidence of capsule complication and its risk factors in Sweden over an 8-year period. SETTING: Fifty-two ophthalmic surgery units in Sweden. DESIGN: Database study. METHODS: Data were collected prospectively in the Swedish National Cataract Register (NCR) from 2002 through 2009. The NCR contains 97.3% of the total number of cataract extractions in Sweden over the 8-year study period. One mandatory variable in the register is capsule complications during surgery. As a means to validate the accuracy of register data on capsule complications, a randomly selected sample of 2400 registrations was compared with corresponding medical records. RESULTS: The analyses were based on 602 553 cataract extractions reported to the NCR. A capsule complication was reported in 12 574 cataract extractions, corresponding to a frequency of 2.09%. The incidence of this complication consistently decreased each year from 2002 to 2006, after which it stabilized. Poor corrected distance visual acuity in the surgical eye (<= 0.1), the occurrence of glaucoma, diabetic retinopathy, and age were among the parameters significantly related to a capsule complication. Some of these parameters also decreased overtime. However, even after adjusting for this, there was an obvious decrease in capsule complications over time. The validity test showed a certain underreporting of capsule complications to the registry, but it was not significant and did not change over time. CONCLUSION: The incidence of capsule complications decreased over time. This may be partly the result of fewer risk factors and of better surgical quality.