title: Risk of pseudophakic retinal detachment in 202,226 patients using the fellow nonoperated eye as reference.
abstract: OBJECTIVE
  To study the risk of pseudophakic retinal detachment (PRD) after first-eye phacoemulsification cataract surgery in Denmark relative to the risk of retinal detachment (RD) in the patients' fellow nonoperated eyes.
  
  
  METHODS
  Register-based cohort study.
  
  
  METHODS
  Danish patients (n = 202 226).
  
  
  METHODS
  All patients underwent uncomplicated first-eye phacoemulsification cataract surgery from 2000 through 2010. Surgeries were identified via the National Patient Registry in Denmark and the Civil Registration Number. The fellow nonoperated eye was used as a reference.
  
  
  METHODS
  Rhegmatogenous RD.
  
  
  RESULTS
  We identified 110 RDs in the fellow nonoperated reference eyes. In these eyes, male sex and younger age were associated significantly with greater risk of RD. We identified 465 PRDs on the cataract-operated eyes. The relative risk of PRD was 4.23. This effect of cataract surgery on the relative risk of RD (the PRD risk ratio) was not statistically significantly modified by sex and age. The PRD risk ratio was not significantly higher in men compared with women (hazard ratio, 1.26); was highest for the 40-year-old cohort and lowest for the 80-year-old cohort; and was highly increased during the first 6 months after surgery and leveled off but remained significantly elevated up to 10 years after cataract surgery.
  
  
  CONCLUSIONS
  Using the fellow nonoperated eye as a reference, this comprehensive matched-design cohort study clearly separates the epidemiologic factors of occurrence of RD from the relative risk of PRD. The epidemiologic factors of RD in the fellow eyes was predicted strongly by age and sex. The 4-fold increase in risk associated with cataract surgery, the PRD risk ratio, was not statistically significantly modified by gender and age. The long follow-up demonstrated a persistently significantly elevated relative risk of PRD up to 10 years after cataract surgery. Because the fellow eye was used as reference, the PRD risk ratio can be considered a true etiologic effect of cataract surgery.
authors.affiliation: Department of Ophthalmology, Glostrup University Hospital, Copenhagen, Denmark. Electronic address: sorensolborg@gmail.com.
authors.forename: Søren S
authors.initials: SS
authors.lastname: Bjerrum
authors.affiliation: The Patient Insurance Association, Copenhagen, Denmark.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Mikkelsen
authors.affiliation: Department of Ophthalmology, Glostrup University Hospital, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: La Cour
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification; D011183:Postoperative Complications; D019591:Pseudophakia / Q000209:etiology*; D012042:Registries; D012163:Retinal Detachment / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013997:Time Factors; D014821:Vitrectomy