Macular choroidal thickness in normal Egyptians measured by swept source optical coherence tomography

Background: To provide a normal database of choroidal thickness (CT) in nine Early Treatment Diabetes Retinopathy Study (ETDRS) subfields in Egypt using deep-range imaging swept source optical coherence tomography (DRI SS OCT). Methods: This study included a total of 129 eyes of 71 normal Egyptian subjects, comprising 63 males and 66 females. The mean age was 36.85 +/- 14.22 years (range, 16-67 years). The mean axial length was 23.84 +/- 0.78 mm. CT was measured in nine subfields as defined by the ETDRS-style grid using a DRI SS OCT, and line measurements of subfoveal choroidal thicknesses (SFCT) were also performed. Results: Mean SFCT was 300.87 +/- 72.256 mu m for ring measurements and 319.72 +/- 76.45 mu m for line measurements (P = 0.04). CT was higher in the superior and temporal quadrants than the inferior and nasal quadrants. A negative correlation between subfoveal choroidal thickness and age was detected in all regions (P < 0.001) except the nasal quadrant. A negative correlation between the SFCT and axial length was also detected (P < 0.001). Males tended to have a thicker choroid than females; however, the difference was not significant. Conclusions: DRI SS OCT provides a topographic map of choroidal thickness with an ETDRS layout. This study establishes, for the first time, a normal database for CT in the Egyptian population. Age and axial length were associated with choroidal parameters in healthy subjects. Line measurements of the SFCT differed significantly from SFCT ring measurements, so it is recommended that each method be compared independently.