Different Effects of Aging on Intraocular Pressures Measured by Three Different Tonometers.

This study aimed to compare intraocular pressures (IOP) using different tonometers, Goldmann applanation (IOP), non-contact (IOP), and rebound (IOP), and to assess the effects of aging and central corneal thickness (CCT) on the measurements. The IOP, IOP, IOP, mean patient age (65.1 ± 16.2 years), and CCT (521.7 ± 39.2 µm) were collected retrospectively from 1054 eyes. The differences among IOPs were compared by the paired -test. Possible correlations between devices, age, and CCT were assessed by linear regression analyses. The effects of age and CCT on the IOP reading were assessed by mixed-effects regression models. The IOP values were 2.4 and 1.4 mmHg higher than IOP and IOP, respectively; the IOP was 1.0 mmHg lower than IOP ( < 0.0001 for all comparisons). The IOPs measured by each tonometer were highly correlated with each other ( = 0.81-0.90, = 45.2-65.5). The linear regression analyses showed that age was negatively correlated with IOP ( = -0.12, = -4.0) and IOP ( = -0.14, = -4.5) but not IOP ( = 0.00, = -0.2); the CCT was positively correlated with IOP ( = 0.13, = 4.3), IOP ( = 0.29, = 9.8), and IOP ( = 0.22, = 7.2). The mixed-effect regression models showed significant negative correlations between age and IOP ( = -2.6) and IOP ( = -3.4), no correlation between age and IOP ( = 0.2), and a significant positive correlation between CCT and the tonometers ( = 3.4-7.3). No differences between IOP and IOP were seen at the age of 38.8 years. CCT affects IOPs from all tonometers; age affects IOP and IOP in different degrees. IOP tended to be higher than IOP in young subjects, but this stabilized in middle age and became higher in older subjects.