With the summer upon us, people are taking out their sunscreen and shades to help protect against the sun's harmful rays. But are your sunglasses doing more harm than good?

Dark sunglasses actually may cause more problems if they don't have adequate ultraviolet (UV) protection. When you wear dark sunglasses, your pupils enlarge to allow light in, but if your sunglasses don't have proper UVA protection, you may be letting in the sun's harmful rays instead of keeping them out, warns the American Academy of Opthalmology.

Studies show that exposure to bright sunlight can increase the risk of developing cataracts and macular degeneration, both leading causes of vision loss among older adults. The more exposure to bright light, the greater the chance of developing these eye conditions, said Dr. Martin Mainster, Academy spokesman.

Here's how to ensure your eyes are protected, the Academy noted:

• Select sunglasses that block ultraviolet rays. Don't be deceived by color or cost. The ability to block UV light is not dependent on the darkness of the light or the price tag.

• Ideally, your sunglasses should wrap all the way around to your temples, so the sun's rays can't enter from the side.

• In addition to your sunglasses, wear a broad-rimmed hat to protect your eyes. Don't be fooled by a cloudy day. The sun's rays can pass through the haze and thin clouds.

• Even if you wear contacts with UV protection, remember your sunglasses.

In addition to the damage caused by a lifetime of exposure to bright sun, you need to protect your eyes from acute damage caused by single outings on very bright days. Excessive exposure to ultraviolet light reflected off sand, snow or pavement can damage the cornea, the eye's surface. Similar to a sunburn on your skin, corneal ultraviolet injuries are painful, but usually heal quickly.