These are photochromic lenses. When they're exposed to ultraviolet light, they become darker or change to a different color. Most brands remain pretty light when you're driving, because windshields block most UV light. To learn more about photochromic lenses and to compare the advantages of the major brands, please keep reading to see more about photochromics & tints. Photochromic lenses such as those made by Transitions Optical are clear (or nearly clear) indoors and darken automatically in response to sunlight outdoors. They also protect your eyes from 100 percent of the sun's harmful ultraviolet radiation. These features make photochromic lenses a great convenience, because they reduce your need to wear prescription sunglasses in most outdoor conditions.

Anti-reflective coating, also known as AR coating, helps you to see through your eyeglasses more easily, lets others see your eyes better and eliminates the annoying white glare spots in photos taken with a flash. Each layer is scientifically calculated to block reflected light. The result is that you'll see a reduction in glare, annoying reflections and halos around lights. This is a great safety benefit when you're driving at night. Also, anti-reflective coating reduces both internal and external reflections on the lenses themselves, creating a nicer cosmetic appearance. Internal reflections appear as rings that make lenses look thick. External reflections mask your eyes from a clear, complete view when someone is looking at you.

- Consistently sitting too close to the TV or holding a book too close - Losing his or her place while reading - Using a finger to follow along while reading - Squinting - Tilting the head to see better - Frequent eye rubbing - Sensitivity to light - Excessive tearing - Closing one eye to read, watch TV or see better - Avoiding activities that require near vision, such as reading or homework, or distance vision, such as participating in sports or other recreational activities - Complaining of headaches or tired eyes - Receiving lower grades than usual Schedule an appointment with your eye doctor if your child exhibits any of these signs.

- If you're buying just one pair of glasses, avoid trendy frames that could go out of style quickly. - If you're buying glasses for a child whose prescription changes often, ask to have new lenses put in the old frames, rather than buying new frames each time. - Choose a style with spring hinges, which allow the temples to flex slightly outward without breaking the eyeglasses. - Ask for scratch-resistant coating. - Follow your eye care professional's instructions for the proper care of your glasses. Improper care is a primary cause of damage to anti-reflective coating and can cause other problems as well.

You should see your eye doctor if you're having any sort of problem with your vision. However, we can tell you some reasons this might be happening. This is a common problem for computer users who wear bifocals (which correct near and far vision) or reading glasses (which correct near vision), because computer monitors tend to be in your intermediate vision, neither near nor far. The solution is to ask your eye doctor about intermediate vision correction, in the form of either computer glasses, progressive lenses or trifocals. Sometimes, the problem is that the near-vision portion of your glasses is not compatible with what you're doing. Golfers, for example, benefit from having that portion placed very low and in the inside corner, so that it doesn't interfere with their game. Read more about these special types of multifocals, called occupational lenses.

You should get a new pair if your prescription has changed; your doctor will let you know. Therefore, it's important to know how often to visit the eye doctor. It depends on many factors, but as a general rule, you should go once a year or once every two years. Your doctor can tell you what schedule is right for you. If your prescription doesn't change very often, or at all, just get new glasses when you're tired of your old ones or they go out of style.