High cholesterol is the name given to having too much of a fatty substance in your blood. This substance, known as cholesterol, can lead to blockages in your blood vessels.
Blocked blood vessels raises the risk of heart attacks and strokes, as it limits the blood supply to the heart and the rest of the body.
You're more likely to have high cholesterol if you eat certain foods, it's been revealed.
It's not always easy to know whether you have high cholesterol, as there aren't any obvious symptoms.
You may be at risk of the condition if you develop a a subtle sign in your eyes.
Some patients with high cholesterol may find that they have a blue/white ring appear in their eyes.
The ring, which is officially known as an arcus, indicates high triglyceride levels, according to Ophthalmic Consultants of London's retinal surgeon, Mr Shahram Kashani.
The ring will be grey, and tends to start at the top and bottom of the iris, before forming a complete circle.
The ring is believed to be a fatty deposit, which hints that the body is overloaded with fat - a risk factor for heart disease.
"The eyes can reveal if a person has a high level of cholesterol," Kashani told Express Health.
"A bluish or white ring – called an arcus – around the cornea is a common sign of ageing, but it can also indicate high cholesterol and triglyceride levels, both of which can increase your risk of heart attack or stroke.
"The retina can also be adversely affected if you have high cholesterol. If a cholesterol clot breaks off and ends up in your eye, it can be very serious.
"In the worst cases, such clots can cause the eye equivalent of a stroke. If they lodge in the retinal artery, they can cause complete or partial blindness."
The arcus may not necessarily be visible to the naked eye, however, he added.
You should always attend your routine eye tests to avoid the complications of clots, warned Kashani.
Around 45 percent of people over 40 are believed to have this ring around their iris.
The presence of an arcus has been linked to some of the risk factors for coronary heart disease.
High cholesterol may be caused by eating lots of fatty foods, or by not doing enough exercise.
Obesity, smoking, and drinking lots of alcohol, all contribute to your cholesterol levels.
Medication can help to keep your cholesterol levels in check, but it's also important to stick to a healthy diet, and to do regular exercise.
Everyone should aim to eat at least five portions of fruit and vegetables every day, as well as 150 minutes of exercise every week.