Retinal vascular caliber in patients with newly diagnosed iron deficiency anemia

•The central retinal artery equivalent is significantly narrower in patients with iron deficiency anemia.•Hemoglobin level was associated with central retinal artery equivalent and central retinal vein equivalent in patients with iron deficiency anemia. To evaluate the retinal vascular caliber using fundus photography in patients with newly diagnosed iron deficiency anemia (IDA). This study included 56 eyes of 28 female patients with IDA and the 56 eyes of 28 age- and sex-matched healthy participants. Retinal vascular calibers were measured using image analysis software from fundus photographs. The central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE) and arteriole-to-venule ratio (AVR) were compared between groups. Linear regression analysis was used to quantify the relative impact of hemoglobin level on CRAE, CRVE, and AVR. The CRAE was significantly narrower in patients with IDA. However, no such difference appeared between groups in CRVE. AVR was significantly lower among patients with IDA than in the control group. Linear regression analysis revealed that in patients with IDA, hemoglobin level was associated with CRAE and CRVE but not with AVR. Among non-anemic individuals, there was also no association between hemoglobin level and CRAE, CRVE, or AVR. Our results showing that the CRAE is significantly narrower in patients with IDA than in healthy non-anemic individuals suggests that vascular caliber may reflect early microvascular alterations resulting from IDA. Added to that, hemoglobin level was associated with CRAE and CRVE in our linear regression analysis of patients with IDA. Certain changes in retinal vascular caliber are also clearly associated with high blood pressure, cardiovascular risk, and mortality. It may be critical to identify all alterations in retinal vascular caliber in order to prevent potential ocular and systemic disorders in patients with IDA.