Factors Affecting Intraocular Pressure Measured by Noncontact Tonometer

Purpose

To investigate the mean values of intraocular pressure (IOP) measured with non-contact tonometer (NCT) and evaluate the factors that may affect IOP.

Methods

A total of 850 subjects who were admitted to our clinic between March 2005 and February 2006 were recruited for the study. Subjects having blepharitis, conjunctivitis, corneal diseases, glaucoma suspicion, or glaucoma were not accepted to the study. All subjects were questioned about systemic diseases. IOP measurement with NCT and central corneal thickness (CCT) with ultrasound pachymetry were performed for each patient between 9 and 11 AM.

Results

The mean ages of 367 (43.2%) male subjects and 483 (56.8%) female subjects were 43.9±18.1 and 40.7±18.0 years ± SD, respectively. Since right and left eye IOP, CCT, and keratometric values were significantly correlated, right eye values were used for statistical purposes. Mean IOP values in males and females were 13.2±3.0 and 13.5±2.9 mmHg, respectively. Mean CCT values were 552.5±34.7 μm for males and 550.1±34.3 μm for females. In multiple regression analysis, IOP was found to be associated with gender, refractive error, CCT, and the presence of diabetes mellitus (DM).

Conclusions

Gender, CCT, the presence of DM, and refractive error may be significantly associated with IOP in this particular population.

Factors influencing central corneal thickness in a Turkish population

PURPOSE

The aim of this study is to find out the central corneal thickness (CCT) values for a Turkish patient group and to investigate the possible influences of age, sex, IOP, refractive status, keratometry readings, systemic disorders (hypertension, diabetes mellitus, hyperlipidemia, heart disease and asthma) on CCT values.

MATERIALS AND METHODS

Six hundred twenty five subjects (276 male (44%), 349 female (56%)) of ages 6 to 88 years were recruited. Subjects who had corneal diseases, purulent conjunctivitis or blepharitis were excluded. Refraction and keratometry readings were made by MRK-3100 premium auto-ref/keratometer, IOP was measured by Reichert AT-555 auto noncontact pneumotonometer.

RESULTS

Mean age was 44.1 +/- 16.6 years +/- SD for male subjects, 41.0 +/- 16.9 for females. Mean CCT +/- SD values for male was 552.2 +/- 35.9 microm, for female was 552.3 +/- 35.4 microm, respectively. There was no significant difference between right and left eye CCT values for both genders. Age and CCT was not correlated for the whole study group but there was a slight negative correlation in male subjects. IOP and CCT had moderately significant correlation for males and females. There was a slight significant correlation between Kh-Kv and CCT values for the whole group. In a multivariate regression model only Kv values seemed to affect CCT values.

DISCUSSION

There are studies showing the variation of CCT values among different nations and ethnicities. There is no agreement about the relationship between age, IOP, Kh-Kv, spherical equivalence of refractive error, systemic disorders, menopause and CCT. In our study CCT was correlated with Kh-Kv and IOP in correlation analysis but in multivariate regression analysis only Kv appeared to influence corneal thickness.