We present a case of internal carotid artery dissection (ICAD) in the precranial segment, which caused binocular visual impairment in a 49-year-old man during a marathon race. The incident lasted 3 h, after which the symptoms resolved. Imaging tests showed internal carotid artery dissection. No ophthalmologic changes were identified. After 6 weeks of ineffective non-invasive treatment the patient underwent vascular surgery - stent implantation into the damaged artery. Detailed diagnostic tests and adequate treatment allowed us to achieve a good clinical result. Upon the suspicion of ICAD it is recommended to extend standard Doppler ultrasound performed with a linear transducer and evaluate the proximal segment of the internal carotid artery with a curved transducer as well.