The final 4 red flags

11. Red flag: Sudden double vision, dim vision, or loss of vision

What it means: These are the visual warning signs of stroke.

More clues: The other signs of stroke include sudden numbness or weakness of the arm or leg or face, typically on just one side of the body; trouble walking because of dizziness or loss of balance or coordination; slurred speech; or bad headache. In a large stroke (caused by a blood clot or bleeding in the brain), these symptoms happen all at once. In a smaller stroke caused by narrowed arteries, they can occur across a longer period of minutes or hours.

What to do: Seek immediate medical help by calling 911.

12. Red flag: Dry eyes that are sensitive to light

What it means: Sjogren's (pronounced "show-grins") syndrome is an immune system disorder. It impairs the glands in the eyes and mouth that keep them moist.

More clues: Sjogren's usually affects women over age 40 with autoimmune disorders such as rheumatoid arthritis or lupus. Usually the eyes and mouth are affected together. The person may also have vaginal dryness, dry sinuses, and dry skin. Because of a lack of saliva, it can be difficult to chew and swallow.

What to do: A doctor can diagnose Sjogren's through testing. Artificial lubricants (such as artificial tears) are usually necessary to protect the eyes, as well as to improve eating. Drinking plenty of water also helps.

13. Red flag: Sudden difficulty closing one eye, inability to control tears in it

What it means: Bell's palsy is an impairment of the nerve that controls facial muscles (the seventh cranial nerve), causing temporary paralysis in half the face. It sometimes follows a viral infection (such as shingles, mono, or HIV) or a bacterial infection (such as Lyme disease). Diabetics and pregnant women are also at higher risk.

More clues: Half of the entire face, not just the eye, is affected. Effects vary from person to person, but the overall effect is for the face to appear droopy and be weak. The eyelid may droop and be difficult or impossible to close, and there will be either excessive tearing or an inability to produce tears. The effects tend to come on suddenly.

What to do: See a doctor. Most cases are temporary and the person recovers completely within weeks. Rarely, the condition can recur. Physical therapy helps restore speaking, smiling, and other tasks that require the facial muscles working in unison, and it also helps avoid an asymmetrical appearance. Professional eye care can keep the affected eye lubricated and undamaged.

14. Red flag: Blurred vision in a diabetic

What it means: Diabetics are at increased risk for several eye problems, including glaucoma and cataracts. But the most common threat to vision is diabetic retinopathy, in which the diabetes affects the circulatory system of the eye. It's the leading cause of blindness in American adults.

More clues: The changes linked to diabetic retinopathy tend to show up in people who have had the disease for a long time, not those recently diagnosed. The person may also see "floaters," tiny dark specks in the field of vision. Sometimes diabetes causes small hemorrhages (bleeding) that are visible in the eye. There's no pain. People with poorly controlled blood sugar may have worse symptoms.

What to do: Someone with diabetes should have a dilated eye exam annually to catch and control the earliest stages of retinopathy, glaucoma, cataracts, or other changes -- before they manifest as changes you're aware of.