1. Glaucoma is when you have optic nerve damage and visual field loss. Higher than normal eye pressure (intraocular pressure or IOP) without signs of glaucoma is known as ocular hypertension (high IOP).

2. High eye pressure is not the sole cause of glaucoma, but it is a significant risk factor. If you use medication to lower your eye pressure, be sure to apply your drops consistently and exactly the way your doctor prescribed. Otherwise they won't work well.

3. You may not be able to prevent glaucoma, but you can prevent vision loss from glaucoma. In fact, glaucoma is the number one cause of preventable blindness. Over 4 million Americans (and almost 70 million people worldwide) have glaucoma, yet experts estimate that half of them don't even know it. The key to preserving vision is early detection and treatment. IOP-lowering medications reduce eye pressure to prevent damage to the optic nerve. Surgical options are also available.

4. There is no single number that applies to everyone. An eye pressure level that's high for one person may be perfectly normal for another. The important factor is the amount of pressure your optic nerve can take without being damaged. This is different for everyone. One reason may be related to the thickness of the cornea. Researchers are discovering that corneal thickness (or thinness) can influence your eye pressure reading - and even conceal the true pressure in your eye. For example, if you have thin corneas, your real eye pressure may be higher than your reading shows. That's why comprehensive dilated eye exams are so important.

5. There are a number of different tests that provide your doctor with various pieces of information. These include measuring your eye pressure, looking inside your eye to examine your optic nerve, testing your peripheral vision, checking the thickess of your cornea, and more. Together, the results can help your doctor make the proper diagnosis.

6. If you have not experienced vision loss, you should be able to stay behind the wheel. But be on the lookout for changes to your sight that could compromise your ability to drive safely. These could include any loss of peripheral vision, which would make it hard to see other vehicles coming in from the side, any blurring of vision, and a greater sensitivity to sunlight during the day or headlight glare at night. If bright light bothers you, you may want to consider tinted lenses. Try brown during the day and yellow or amber at night. If you do begin to develop any of these warning signs, take heart. Even some people with advanced glaucoma may still be licensed to drive with certain restrictions.

7. If you miss a dose and it's less than 24 hours until your next dose, skip it and return to your normal scheduled time. Do not exceed more than one dose in a 24-hour period. Never double your dose.