Persisting styes.

Styes are certainly an annoying thing. They're essentially an infected bump on the eyelid that rubs on your eye, causing irritation.

A stye that doesn't go away for 3 months or longer, or a reoccurring stye, could be a sign of a rare form of cancer called sebaceous gland carcinoma. See a doctor immediately.

Yellowish whites of the eyes.

A yellowing of the eyes is called Jaundice. Jaundice typically effects people who have a disorder of the bile ducts, gallbladder, or liver. If your eyes begin yellowing, see a doctor.

Bulging eyes.

If your eyes seem to be protruding or bulging, it could be a sign of an overactive thyroid gland, otherwise known as hyperthyroidism.

Sudden double vision, dimming, or loss of vision.

Suddenly experiencing any of the above symptoms could be early warning signs of a stroke. This is a serious condition that needs immediate medical attention.

Additionally, look for arm and/or leg weakness, facial drooping, difficulty speaking, and sudden numbness.

Blurred vision in diabetics.

If you suffer from diabetes, chances are you'll have some kind of issue with your eyes at some point. Experiencing blurred vision when you have diabetes requires medical attention.

Increases in the use of screens contributes to this problem as well, but the leading cause among diabetics is issues of circulation to the eye. See a doctor about your options.