['\u2002 To study the associations between serum 25-hydroxy-vitamin D (25(OH)D) levels, vitamin D administration and intraocular pressure (IOP).', '\u2002 The design of the study included a nested case-control study and a randomized controlled intervention trial. In the first part, healthy Caucasians with high or low serum 25(OH)D levels were recruited from a population-based study. IOP of the right eye was measured by the use of a rebound tonometer. In the second part, those with low serum 25(OH)D levels were randomized to receive either capsules of vitamin D3 20,000 IU twice per week or placebo for 6 months before IOP was measured again.', '\u2002 Intraocular pressure in the 87 participants with low serum 25(OH)D levels (mean 40.1±12.9 nm) did not differ from IOP in the 42 participants with high serum 25(OH)D levels (mean 85.1±14.0 nm) (15.9±3.3 mmHg versus 15.6±3.1 mmHg, p= 0.56, independent t-test). After intervention, IOP decreased by -0.8± 2.1 mmHg (p = 0.017, paired t-test) in the vitamin D group (n= 39) and -0.8±2.5 mmHg (p= 0.059) in the placebo group (n= 39), but the change was not significantly different between the groups (p= 0.92, independent t-test).'] Does vitamin D and intraocular pressure -- result from a case-control and an intervention study?