Measurement of Ocular Pulse Amplitude Using Dynamic Contour Tonometry and the Influence of Central Corneal Thickness, Akial Lenght and Anterior Chamber Depth on the Measurements

Purpose: To investigate the effects of age, sex, intraocular pressure (1OP), central corneal thickness (CCT), corneal curvature, anterior chamber depth (ACD) and axial length on OPA measurements using dynamic contour tonometer (DCT) in healthy subjects. Materials and methods: Fifty-three eyes of 53 healthy individuals were included in this prospective study. After keratometric measurements, OPA and IOP were measured using Pascal DCT under topical anesthesia. The CCT was determined with the aid of ultrasonic pachymeter. After that, ACD and axial length of the subjects were measured by A scan ultrasonography. Pearson correlation analysis was used to determine the association between OPA and other parameters. Results: The mean age of 53 subjects (34 female, 19 male) who were included in the study was 52,68 +/- 8,29 years. Mean OPA was 2,81 +/- 1,01 mm Hg. Mean IOP was 15,89 +/- 2,39 mm Hg, corneal curvature was 7,80 +/- 0,23 mm, CCT was 556,30 +/- 32,80 mu m, ACD was 2,91 +/- 0,32 mm and axial length was 23,14 +/- 1,10 mm. There was no correlation between OPA values and age, CCT or ACD of the subjects (p>0.05). There were significant negative correlations between OPA and axial length (p<0.001 r=-0.49) and between OPA and corneal curvature (p=0,024 r=-0,31). There was a significant positive correlation between OPA and IOP measurements (p=0,007 r=0,37). OPA values were statistically higher in females than in males (p=0,03). Conclusion: OPA values are found to be correlated with axial length, corneal curvature and IOP. There is no correlation between OPA and CCT. Since OPA measurements using DCT were less effected by corneal biomechanical properties, it gives more reliable information about ocular blood flow.