Intraocular pressure changes over 21 years - a longitudinal age-cohort study in northern Sweden

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.

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.

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).

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.