Anterior Segment Biometry Using Spectral Domain Optical Coherence Tomography

Abstract
Background: AS-OCT allows a non-contact examination with high resolution imaging of the anterior segment of the eye of human. It enables assessment and documentation of the condition of the eye's anterior segment.
Aim of Study: Evaluation of Anterior Segment Optical Coherence Tomography (AS-OCT) in quantitative analysis of the anterior segment of the eye. Analysis of association between Central Corneal Thickness (CCT), Corneal Epithelial Thickness (CET) and corneal radius of curvature (CC) meas-ured by OCT in relation to other parameters; age, sex, refraction and Intra Ocular Pressure (IOP).
Patients and Methods: The present study included 100 normal eye of 100 hundred patients aged from 20:60 years. CCT, CET and radius of CC were measured using anterior segment Spectral Domain Optical Coherence Tomography (SD-OCT) (3D OCT-2000 (Topcon Corp., Tokyo, Japan)). IOP was measured using Goldman applanation tonometer. Measurements of refractive status were detected by autore-fractor and then confirmed by retinoscopy and spherical equivalent was calculated of astigmatic patients.
Results: Total number of 100 eye were evaluated for the study. 34 eyes were emmetrope, 34 eyes were myopes and 32 eyes were hypermetropics. The CCT average was 541.62mm (SD ±21. 11). This study showed no statistically significant difference between CCT in myopes, hypermetropes and em-metropes). Mean IOP was 15.65mmHg (SD ±1.56). The correlation between IOP and CCT was highly significant (r= 0.867; p<0.001). The CET average was 54.80 (SD ±2.68). The study has shown the positive relation between CET and CCT. The mean radii of corneal curvature was vertically 7.61 (SD ±0.27) and horizontally was 7.61 (SD ±0.25). We found a statistically relation between error of refraction and corneal radius of curvature. Eyes with more myopic refractive error tend to have steeper corneas with less radii of curvature on controversy with hypermetropic eyes. No correlation between age or sex to all the above.
Conclusion: This study has shown that CCT has no cor-relation with degree of refractive error. Whereas there is significant correlation between CCT and IOP and CET as well. The study also has shown that there were no associations between corneal radius of curvature and IOP. However, myopic eyes shows tendency for smaller radii of curvature whereas in hypermetropic ones the radii of curvature tend to be longer. There was no significant relation between age and sex and any parameter of the study. Our findings highlight the value of spectral domain AS-OCT measurements as a standard tool in anterior segment analysis.