When you look into your eyes, it is perhaps because you are preparing for an interview. Maybe you’re just trying to figure out if they’re red or bloodshot, irritated by allergies or maybe a bad night. When doctors look at you, they can see a lot more. The eyes will also be the proverbial window of the soul, but they show just as much on the health and the amount of information they can reveal is impressive. Many diseases cause symptoms throughout the body – on the skin, in the mouth, some even on the nails – but the eye is a place that reveals a particularly high percentage of health claims.

“Watching an eye is a fabulous experience,” Dr. Charles P. Wilkinson, retinal specialist and clinical spokesperson for the American Academy of Ophtalmology told Business Insider, adding: “It’s the only place where you can see pulsing blood vessels without consequences; you can then see the optic nerve, which is part of the brain “. With so much in sight, over thirty ocular conditions can reveal as many symptoms. This is why ophthalmologists and opticians are often among the first to notice certain problems.

An eye exam can be the first detector of critical illnesses, such as diabetes, high cholesterol or even a brain tumor, according to the VSP Vision Care insurance company. VSP president Jim Mc Grann told Business Insider how these tests revealed that many patients, ” if they did not go to an eye specialist, would now go around with triggered diseases such as time bombs.”

1. Red spots, caused by drops of blood, could be a symptom of diabetes – a terrible disease that will affect 40% of Americans, according to the Centers for Disease Control and Prevention (CDC). If the sugar contained in the blood reaches too high levels, the blood vessels start to stop and swell. This can cause the very thin retina to burst, for example, causing bleeding. If no action is taken, sight can be reduced, or fail completely.

2. Bloodshot eyes may be caused by many other circumstances, such as excessive cough, conjunctivitis or fungal infections.

3. Eyes that burn, swollen or reddened are typical signs of an allergic patient, usually to dust, pollens or animals. The eye drops can help, especially if it contains an antihistamine, which sometimes if taken by mouth is likely to get unwanted effects, such as dry eye, which worsens the problem

4. Ocular dryness is a collateral symptom of both the use of computers and drugs, such as sleeping pills, painkillers, anxiolytics. Autoimmune diseases can also cause dry eye, especially Sjögren’s syndrome, which destroys the secretory glands, affecting mostly older women.

5. With age, most people lose the ability to focus on close subjects, such as when reading the restaurant menu, but some drugs – antihistamine antidepressants, diuretics – cause presbyopia prematurely.