title: Intraocular pressure changes over 21 years - a longitudinal age-cohort study in northern Sweden.
abstract: OBJECTIVE
  To follow intraocular pressure (IOP) and the influence of pseudoexfoliation (PEX) and cataract extraction in an age-cohort in northern Sweden; patients were followed prospectively for 21 years from age 66 to 87 years.
  
  
  METHODS
  Three Hundred and thirty-nine individuals, randomly selected from an age-cohort born in 1915 underwent ophthalmological examination including measurement of IOP with Goldmann applanation tonometry, screening for PEX and glaucoma. Follow-up examinations were performed three times with 7-year intervals. Medical records were reviewed for dates of cataract surgery and glaucoma treatment. A linear mixed model was used to analyse the impact of sex, eye (right/left), PEX, cataract extraction and time on IOP.
  
  
  RESULTS
  Without cataract surgery, the IOP from age of 66 to 87 years, increased by 0.05 mmHg/year (p < 0.001). If cataract surgery was included in the model, no significant change in IOP over time was found. The estimated contribution of PEX to IOP was +2.05 mmHg (p < 0.001), and the contribution of cataract surgery was -2.13 mmHg (p < 0.001). The mean IOP in women was 1.22 mmHg higher than in men (p = 0.001).
  
  
  CONCLUSIONS
  A small but statistically significant increase in IOP with age was detected when excluding eyes that had undergone cataract surgery. PEX was associated with a higher IOP and cataract extraction with a lower.
authors.affiliation: Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, SwedenDepartment of Public Health and Clinical Medicine, Epidemiology and Global Health, Umeå University, Umeå, Sweden.
authors.forename: Siv
authors.initials: S
authors.lastname: Åström
authors.forename: Hans
authors.initials: H
authors.lastname: Stenlund
authors.forename: Christina
authors.initials: C
authors.lastname: Lindén
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002387:Cataract Extraction; D015331:Cohort Studies; D017889:Exfoliation Syndrome / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D011446:Prospective Studies; D013548:Sweden / Q000453:epidemiology; D014065:Tonometry, Ocular
keywords: cataract surgery; intraocular pressure; long-term; longitudinal; pseudoexfoliation