2M.D. Associate Professor, Ulucanlar Eye Training and Research Hospital, Ankara/TURKEY Purpose: To compare central corneal thickness (CCT) measured with ultrasonic (US) pachymetry and anterior segment optical coherence tomography (AS-OCT) in eyes of healthy subjects.
Material and Methods: In this prospective study, CCT measurements were performed in 220 eyes of 110 subjects (48 were men, 62 were women) who had no ocular pathology, initially with AS-OCT after US pachymetry. Statistical analysis of data was carried out using pairedsamples t-test, independent-samples t-test and Pearson correlation analysis.
Results: The mean age was 37.09±13.6 years. The mean CCT obtained by US pachymetry was 545.76±34.66 µm for the right eye and 547.85±34.07 µm for the left eye. They were 523.56±32.78 µm and 523.53±32.67 µm for right eye and left eye respectively obtained by OCT. The CCT measured by US was mean 22.20±8.85 µm thicker for the right eye and 24.32±8.52 µm for the left eye compared to OCT measure which were statistically significant for each side. (p<0.0001). But a significant positive linear correlation between the two methods were observed (Right eye: r=0.967, p<0.0001, left eye: r=0,968, p<0.0001).While the difference between the right eye and the left eye with US pachymetry was -2.08± 7.6 µm (p=0.005), there was no significant difference (0.036±5.8 µm) with OCT (p=0.948).
Conclusion: Central corneal thickness measured by OCT and US pachymetry is highly correlated. However, it is not appropriate for these devices to be substituted for each other in CCT measurements since US pachymetry measures CCT greater than AS-OCT.
Keywords : Central corneal thickness, optical coherence tomography, ultrasonic pachymetry