Comparison and Correlation Analysis of Intraocular Pressure Measured with the Pressure Phosphene Tonometer and the Goldmann Tonometer

ABSTRACT

PURPOSE: To compare the intraocular pressure (IOP) measured by the pressure phosphene tonometer (PPT) and the Goldmann applanation tonometer (GAT) according to the feedback of the IOP measured by GAT and the use of the dominant hand during the measurement. METHODS: In a group of 40 eyes of 40 normal subjects in their twenties and thirties without diagnostic specificity, IOP was measured with PPT three times by themselves and with the GAT by one examiner on 3 different days. In 20 eyes of the feedback group, the subjects were informed of their IOP measured by GAT and were allowed to measure with PPT again. In each group, half of the eyes (20 eyes) were assigned to use the dominant hand to measure the IOP (dominant group) and the other half (20 eyes) were assigned in the other way (nondominant group). RESULTS: In feedback, nonfeedback and dominant groups, comparison of the first day showed statistically significant differences of mean IOP. But on the third day, there were no significant differences among all 4 groups and there were significant correlations. There was a stronger correlation between the two methods in the feedback group (r=0.721) than in the nonfeedback group. The correlation coefficient of all 40 eyes was 0.605 (p<0.001). CONCLUSIONS: PPT has a strong correlation with GAT in the range of normal IOP and is thought to be more useful as a self tonometer for the measurement of both eyes with the periodical measurement of IOP by GAT in clinics.