Comparative Analysis of Retrobulbar Blood Flow in Symmetric and Asymmetric Keratoconus Patients

Background/Objectives: Keratoconus is a progressive corneal disorder characterized by thinning and conical protrusion of the cornea, resulting in visual impairment. This study aimed to evaluate retrobulbar blood flow characteristics in patients with symmetric and asymmetric keratoconus and to compare these parameters with those of healthy individuals. Methods: Participants aged 18-40 years were recruited and categorized into three groups: symmetric keratoconus, asymmetric keratoconus, and healthy controls. Color Doppler ultrasonography was used to measure the pulsatility index (PI) and resistive index (RI) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA). Retrobulbar hemodynamic parameters were analyzed and compared across groups using appropriate statistical methods. Results: The ophthalmic artery PI (oaPI) and central retinal artery PI (craPI) were significantly elevated in both symmetric keratoconus patients and the affected eyes of asymmetric keratoconus patients compared to the control group (p < 0.05). In contrast, the oaPI in the unaffected eyes of asymmetric keratoconus patients was significantly lower than that of controls (p < 0.05). Conclusions: The elevated oaPI and craPI values observed in keratoconus patients suggest that the disease may involve not only corneal structural abnormalities but also alterations in ocular blood flow. These findings may imply a potential vascular component in keratoconus pathophysiology.