A comparison of NCT, Goldman application tonometry values with and without fluorescein

Hakika Erdogan, Ziya Akingol, Ozlem Cam, Sadik Sencan Department of Ophthalmology, Faculty of Medicine, Maltepe University, Maltepe, Istanbul, Turkey  Purpose: The aim of the study was to statistically compare intraocular pressure (IOP) values measured using noncontact tonometer (NCT), Goldmann applanation tonometry (GAT) with fluorescein (fGAT), and GAT without fluorescein (nGAT). The study was also performed to test whether the values obtained using each technique change in accordance with the central corneal thickness (CCT) and refractive and keratometric values.Study design: This study was a prospective study of 188 eyes of 94 healthy volunteers.Methods: IOP was measured using fGAT, nGAT and NCT. CCT, refractive values, and keratometric values were measured, and the correlations and differences in the IOP for each tonometer were investigated.Results: The mean IOP values obtained with the NCT, nGAT, and fGAT were 17.5±3.7, 12.3±2.7, and 12.5±2 mmHg. The mean CCT was 538.2±34.4 µm, the mean refractive value was 0.9±1.2 D, and the mean keratometric value was 43.5±1.5 D. NCT was positively correlated with fGAT and GAT values and was significantly higher than both the values. There were no differences between fGAT and GAT values. No correlation was observed between the CCT and keratometric and refractive values and the difference between NCT and nGAT or fGAT.Conclusion: Differences in the measurements obtained using nGAT and fGAT were insignificant (P>0.05). Both values were positively correlated with NCT measurements (r=0.354, P<0.05) and were independent of CCT, keratometry, and refraction values. nGAT appears to be suitable for use in routine clinic practice. Keywords: fluorescein, intraocular pressure, Goldmann applanation tonometry, noncontact tonometry, central corneal thickness, refractive valu