Luminal and Stromal Areas of Choroid Determined by Binarization Method of Optical Coherence Tomographic Images

Abstract

To determine the proportion of luminal and stromal areas of normal choroids in the optical coherence tomographic (OCT) images obtained by enhanced depth imaging (EDI)-OCT. A prospective, masked, observational cross-sectional study. setting: This study was performed at the Kagoshima University Hospital, Japan. One hundred and eighty right eyes of 180 healthy volunteers (106 women; mean age of 55.9 years) without ocular pathology. observational procedures: The EDI-OCT images of the posterior choroid 7500μm from the optic disc in the horizontal plane were converted to binary images. The total cross-sectional choroidal area, luminal area, and stromal area of the choroid were measured. Correlations between clinical factors and each choroidal structure and ratio of luminal/stromal areas were determined. The correlations of each choroidal structure and the age, sex, axial length (AL), and refractive errors were calculated. The mean total cross-sectional choroidal area was 1.84mm(2) (luminal area 1.21mm(2) and stromal area 0.63mm(2)). Multivariate analysis (standardized partial regression coefficient) showed that age (-0.723, P < .001) was significantly correlated with the reduced area of the choroid, and the correlation was greater than that for the AL (-0.408, P < .001). The ratio of luminal/stromal area was significantly reduced in eyes with longer ALs (-0.531, P < .001), and the strength of the correlation was greater than that of age (-0.389, P < .001). Although both the luminal and the stromal areas decrease with increasing age and with longer ALs, the degree of decrease and areas affected were not the same.