The eyes also contain a wealth of insight about the rest of your body's ability to function. Read on to see what your eyes have to say.

YOU SEE AN AURA.

The sudden appearance of flashing lights, blind spots, or zigzag lines can mean a monster headache is on its way. These visual disturbances, known as anaura, affect around 20% of migraine headache sufferers, according to the National Headache Foundation. The aura's exact relationship to migraine headaches is still being studied. In general, however,auras only affect one side of the person's vision, and they last about an hour or less, as explained by the American Migraine Foundation. Sometimes auras appear without a following headache, and not all migraine sufferers experience an aura beforehand.

If medical science has not yet explained the aura, authors from Lewis Carroll to Hilary Mantel have tried to put words to the visual sensation into words. The esteemed neurologist and writer Oliver Sacks described his first experience with the migraine aura as a young child in The New York Times: "I was playing in the garden when abrilliant, shimmering light appeared to my left - dazzlingly bright, almost as bright as the sun. It expanded, becoming an enormous shimmering semicircle stretching from the ground to the sky, with sharp zigzagging borders and brilliant blue and orange colors."

The zigzag patterns are common to aura sufferers, but the exact cause of their architecture is unknown. If you deal with these weird visions before a crushing headache, take heart in the fact that you're in good company: plenty of luminous artists and thinkers have dealt with the same pain.

YOU HAVE BLURRY VISION.

If a person's vision slowly becomes blurry over time, then an underlying health problem may be to blame. For instance, individuals withglaucoma sometimes experience blurriness or tunnel visionas a symptom of the condition, according to All About Vision. Plus, people with diabetes may experience temporaryblurred vision from high blood sugar, according to WebMD. It can cause the eyes to swell, which distorts vision. Then again, blurry vision that occurs over time could simply point to problems with a person's eyesight.

On the other hand, sudden blurry vision may indicate more serious health conditions. In some cases, asudden blurriness or loss of vision is a strong indicator of a stroke, according to Health. Seek medical help immediately if you think this is even a remote possibility.

YOU HAVE DROOPING EYES.

For many people, drooping eyelids are just a sign of fatigue. If one or botheyelids droops toward the pupil, then this may be myasthenia gravis, an autoimmune neuromuscular disease, according to National Institute of Neurological Disorders and Stroke. The condition results in an overall loss of strength in the skeletal muscles.

YOU'RE SEEING SPOTS

Seeing things that aren't there? It could be eye damage. The uvea, or middle part of the eye, is susceptible to disease, which can result in vision changes. In this case, uveitis refers to the inflammatory diseases that result in the swelling and destruction of eye tissue, according to the National Eye Institute. Symptoms of the condition include floating spots in a person's line of vision (AKA floaters), blurred sight, and light sensitivity, as further explained by the National Eye Institute.

YOU HAVE PINK OR RED EYES.

So many things can cause a red tinge to the eyes, and pulling an all-nighter isn't the only one. For starters, it could be a symptom of conjunctivitis, more commonly known as pink eye. Aninflammation of the eye's transparent membrane, conjunctivitiscauses red, itchy eyes, tearing, and sometimes discharge, according to the Mayo Clinic. Viruses, bacteria, allergens, and irritants can all cause pink eye, although viral cases are the most common - and they are very contagious, as further explained by the Mayo Clinic.

A more serious cause of red eyes isacute angle-closure glaucoma, which occurs when fluid pressure inside the eyes increases too quickly, according to Very Well. This serious medical emergency, which also causes sudden pain and blurred vision, requires immediate attention.

YOU HAVE A RING AROUND YOUR CORNEA.

If a grey or white ring appears around the cornea, take note. This arc or ring, called thearcus senilis, is caused by fat deposits, and it can signify high cholesterolor high triglycerides, according to the Mayo Clinic. For younger people in particular, the appearance of this ring may be reason to see a doctor soon.

YOU HAVE YELLOW EYES.

Lastly, if the eyes are turning yellow, then several conditions could be to blame. For starters, yellow eyes are the main symptom of a condition known asGilbert's syndrome, a liver conditionwhich disrupts the body's ability to process the bilirubin, a yellow compound in blood, according to the Mayo Clinic. This common condition is typically harmless, and it simply results in jaundice, or yellow tinge, to the eyes.

Although Gilbert's syndrome is harmless, yellowing of the eyes could be caused by a number of more harmful conditions.Alcoholism, pancreatitis, and even severe anemiacan all cause yellowing of the eyes, as noted in Very Well. Because it could signify a variety of potential problems, it's best to get this symptom checked out by a doctor.