Quantification of vessels of Haller's layer based on en-face OCT images.

PURPOSE To quantify the vessels of Haller's layer of normal subjects in en-face optical coherence tomographic images. METHODS One hundred and seventy-two normal eyes were studied. En-face images of the top 25% slab of Haller's layer was analyzed. The vessel area, vessel length, and mean vessel diameter were calculated. The vessel running pattern was quantified for the degree of symmetry and designated as the "symmetry index". The coefficient of correlation between each choroidal parameter and the age, sex, axial length, and central choroidal thickness (CCT), were determined. RESULTS The vessel area was 23.4 ±3.6 mm2, vessel length was 164.6 ±24.1 mm, mean vessel diameter was 0.143 ±0.019 mm, and the symmetry index was 58.6 ±6.1%. Multiple regression analysis showed that the vessel area was significantly correlated with the age (R=-0.421, P <0.001) and CCT (R=0.315, P <0.001). The vessel length was significantly correlated with the age (R=-0.391, P =0.024) and CCT (R=-0.410, P <0.001). The mean vessel diameter was significantly correlated with the age (R=-0.107, P =0.024) and CCT (R=0.775, P <0.001). The correlation between the symmetry index and any clinical findings was not significant. CONCLUSION Quantification of en-face images of Haller's layer provide new biomarkers of the choroid.