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 over time. 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. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.