Comparison of choroidal structural changes between children born preterm without retinopathy of prematurity and age-matched children born at full term

•Enhanced depth imaging OCT (EDI-OCT) allows improved visualization of the structural details of the choroidal tissue, and after the definition of the choroidal vascularity index (CVI), the evaluation of the choroidal tissue has moved one step further.•Choroidal tissue is responsible for the vascular supply to the outer retina, retinal pigment epithelium (RPE), and some portions of the optic nerve, and it may play an important role in the development of ROP.•Many studies have evaluated choroidal thickness (CT) using OCT in preterm infants with a history of ROP; however, few studies have examined the effect of prematurity on the choroid with no ROP history.•According to our results; prematurity can affect CT even in the absence of a history of ROP. The decreases in CTs were significant at 2000 µm nasal and temporal from the fovea, although the difference in the CVI was not significant. The impairment of temporal choroidal region was more evident than nasal choroidal region. To evaluate the effect of prematurity on choroidal structure in children born preterm with no history of retinopathy of prematurity (ROP) by comparing them with age-matched healthy children born at full term. Enhanced depth imaging optical coherence tomography (EDI-OCT) scans of children aged 5 to 9 years with a history of prematurity but no history of ROP, and age-matched full-term healthy children were evaluated, retrospectively. Choroidal thicknesses (CTs) were measured at subfoveal (SFCT), 1000 µm temporal and nasal from the fovea (T1, N1), and 2000 µm temporal and nasal (T2, N2) from the fovea. The EDI-OCT images were binarized to stromal (SA) and luminal areas (LA) using the ImageJ software. The choroidal vascularity index (CVI) was calculated by dividing LA by the total choroidal area (TCA). Twenty-nine eyes of 15 preterm children and 41 eyes of 26 full-term children were included. Demographic characteristics including axial length (AL), eye side, age, and the sex of the children in the groups were similar (p>0.05). There was no statistically significant difference in the mean CVI, SFCT, N1, and T1 values between the groups (p>0.05); however, the mean T2 and N2 values were significantly higher in the full-term group than in the preterm group (p