Romantics may say the eyes provide a window into the soul but medical experts claim they provide a portal into our inner health, enabling us to spot the early signs of health conditions from minor to life threatening - in the blink of an eye.
Ophthalmologists can detect and diagnose a range of medical conditions just by looking at the retina - the light sensitive tissue at the back of the eye.
These conditions aren't always restricted to eye diseases like cataracts and glaucoma, but systematic illnesses like diabetes, cardiovascular disease and liver disease, too.
Crucially, these early signs can be picked up before the symptoms appear, which is why it's important to have regular eye tests.
"The most important thing you can do to protect your eyes - and your general health - is to have regular eye tests. This is because most eye diseases can only be seen with specialist equipment that can look at the back of the eye," advises Larry Benjamin from The Royal College of Ophthalmologists.
Apart from maintaining good eye health with regular visits to the optician, there are diet changes you can make that will help improve your eyesight and general eye health:
Eat leafy greens, kale and spinach
Studies show that eating foods rich in carotenoids reduce the risk of age-related eyesight degeneration. Foods rich in the antioxidant include leafy green vegetables like spinach, collard greens and kale.
Add peas and pulses to your diet
Foods high in lutein and zeaxanthin reduce the risk of cataracts. Foods high in these compounds include broccoli, corn, green peas, turnips and zucchini.
Get a blueberry boost
Blueberries have long been linked to the reduction in eye fatigue.
Eat more fruit
Apricots in particular are a rich source of beta-carotene and lycopene - both great antioxidants that promote good eye vision.
Now, take a look to see what your eye could be trying to tell you about your inner health…