For people with carotid artery blockage loss of vision is the only symptom. REUTERS

An eye problem could be the only symptom of a type of fatal cardiovascular condition caused by blockage in the eye's main renal artery. Any temporary loss of vision should not be ignored, say researchers who studied the case of a 77-year-old man.

The condition called "amaurosis fugax," causes a person to lose vision in one eye, for a few minutes at a time due to the interrupted flow of blood to the eye. The patient in this case experienced three such brief episodes of interrupted vision.

Initial examination showed normal vision and pressure in the eye but on closer study, it revealed that a clot was blocking blood supply to his retinal artery. The clot came from the man's carotid artery that supplies blood to the head and eye.

The eyes can provide a good indication of a person's health throughout the body, said Dr Ilias Georgalas, an assistant professor of ophthalmology at the National and Kapodistrian University of Athens, in Greece. The case study of the patient was published in the New England Journal of Medicine.

The patient had no history of eye problems, but was on treatment for high cholesterol levels. The clots result from cholesterol and clumps of platelets (blood cell fragments), Georgalas told LiveScience. Such blocks can result in fatal strokes. In the case study, the clots temporarily closed off the blood supply to one eye. The patient needed a surgery to remove plaque build-up in the carotid. Twelve months later, the man's vision was normal.

Examining the eyes is an easy way for doctors to examine the network of blood vessels in the body, said Georgalas, adding that most vascular problems elsewhere are reflected in the eye. For a large percentage of people with carotid blockage, the eye alone could send the warning signals.

Diabetes, high cholesterol, high blood pressure, a sedentary lifestyle and obesity are all major risk factors for atherosclerosis, says the WebMD. High levels of LDL promote plaque formation in artery linings leading to atherosclerosis, while inflammation and damage to the lining of the vessels under high pressure also contribute. Hardened arteries cannot be treated besides the surgical procedures to destroy the plaque.