Purpose: To study the distribution of choroidal thickness (CT) in and outside of the vascular arcade, as well as at the fovea in healthy eyes using spectral-domain optical coherence tomography (OCT).
Methods: Seventy healthy eyes were examined with OCT to obtain nine horizontal lines in and outside of the vascular arcade. Nine points including the central point of the line were chosen in 0.5-mm intervals to calculate CT. CT was measured at a total of 81 points in each patient to construct a map of CT distribution.
Results: Average subfoveal CT showed a significant relationship with age (P < 0.001) and axial length (P = 0.001). In all nine horizontal lines, CT showed a rough trend of being thickest at a particular point and decreasing thereafter. The aspect of CT distribution was different among the nine horizontal lines (P < 0.001), and the near superotemporal line displayed the thickest choroid among the lines. The difference of the trend between temporal vertical lines was significant as well (P < 0.001).
Conclusions: The CT generally decreased with age, but it decreased much faster in old age than in relatively younger people. CT displayed large variations among different points in and outside of the vascular arcade. The thickest choroid was located at the point superior to the fovea, not the fovea itself. Such physiological variations should be considered when interpreting pathologic changes of the choroid.