Method: 57 eyes of 30 AF patients and 59 eyes of 30 volunteer examined in our eye clinic for different reasons were included in our study. Choroid thickness was measured at the fovea, at points 1mm temporal to the fovea, and at points 1 mm nasal to the fovea in a horizontal section. The mean choroidal thickness of the two groups was compared.

Result: There was no statistically significant difference for age and gender between two groups (p= 0,07, 0,796 respectively). The mean choroidal thicknesses in nasal, temporal submacular and the subfoveal region was lower in AF group for both eye separately. In each group, there was no signifi cant difference between right and left eye for nasal submacular, temporal submacular and subfoveal choroidal thickness.

Conclusion: Choroidal thickness of AF patients is thinner compared to control group. This effect may be the result of the microvascular effect of AF. Keywords : Atrial fibrilation, choroidal thickness, endothelial dysfunction