The Comparison of The Subfoveal Choroidal Thickness Measurements Obtained Using the Inverse and Straight Images of Spectral Domain Optical Coherence Tomography in Healthy Subjects

Abstract

Objective: To measure subfoveal choroidal thickness in healthy subjects using the inverse and straight images of spectral-domain optical coherence tomography. Materials and Methods: 50 eyes of 50 subjects with no retinal or choroidal disease and refractive error more than -6 diyopter and any systemic vascular disease were scanned using SD-OCT. The choroidal thicknesses were measured using the inverse and straight sectional images. The subfoveal choroidal thicknesses obtained in both methods were compared with each other. Results: The mean age of the subjects was 32.4 (ranged from 18 to 45) years. They included 20 (%40) women and 30 (%60) men. In all eyes retinal structure was normal as optical coherence tomographic, foveal contours were present. The visual acuities of all subjects were 1.0 to Snellen lines. The mean subfoveal choroidal thickness in the measurements obtained using the inverse and straight sectional images were 285+/-65 μm (ranged from 170 to 388) and 287+/-66 μm (ranged from 175 to 385), respectively. The difference between both subfoveal choroidal thicknesses was not statistically significant (p>0.05). Conclusion: Currently, the importance of choroidal thickness in the diagnosis and follow-up of numerous retinal and choroidal diseases has been increased. The measurements the choroidal thickness was performed using the OCT mode called the 'Enhanced Deep Imaging. However, any OCT device has not this mode. The choroidal thickness can also be measured using inverse image but no EDI mode. Although there is no difference between both methods for healthy subjects, the usage of inverse mode can provide easy determination. Key Words: Optical Coherence Tomography; Straight Image; Inverse Image; Choroidal Thickness; Healthy Subjects.