Many people find that polarized sunglasses help them to see better outdoors. Even indoors, some people prefer to have polarized lenses in their glasses. How do these lenses work?
What is polarization?
In general, light reflects from a surface in all directions. Rather than being lined up, the light waves are at all different orientations. However, when light reflects off a flat surface, the light waves will tend to be lined up in a more uniform direction. This is usually a horizontal direction, because most of the surfaces that cause this are horizontal. For example, the reflection from the water on a sunny day or the reflection from a road will contain light waves that are lined up in this way. This causes the intensity of light that we perceive as glare. It can reduce visibility and can also be uncomfortable.
Polarized lenses contain a filter that only lets in light waves that are vertical or close to vertical. They block light waves that are aligned horizontally. This blocks the glare, but still allows enough light through to see the objects around you. They don’t have to be sunglasses; regular clear lenses can also be polarized, to reduce glare.
When are polarized lenses useful?
Polarized lenses are particularly useful for cutting down on glare when you’re outdoors. If you’re on the water (for example, kayaking or boating), then you’ll be especially glad to have polarization, because the glare from water can be very intense. Even when you’re driving on a sunny day, polarized lenses can help to make you more comfortable. They often reduce the problems that some people experience as a result of glare, such as eye strain and headaches. They can also improve visibility.
One exception is downhill skiing. While you definitely need sun protection for your eyes in this situation, many experts recommend against using polarized lenses. This is because the glare from a patch of ice can help a skiier to see the ice in time to avoid injury.
Polarized lenses can also prevent the viewing of certain types of screens, because the screen itself polarizes the light. If all of the light from the screen is going in the same direction as the filter on the lenses, then you won’t be able to see the screen while wearing the polarized lenses. (If you look at your phone or a digital clock while wearing your polarized lenses and you can’t see it, that’s why!) Someone who needs to see screens well for safety (for example, a pilot) should choose non-polarized lenses to wear during that activity.
Do you need prescription sunglasses?
If you wear prescription lenses, then you might benefit from a pair of prescription sunglasses with polarized lenses, in order to allow you to comfortably spend time outdoors when it’s sunny. We offer a variety of lens options here at our Carlsbad CA eye clinic. And if you’re hoping to get rid of your prescription lenses for good, we offer laser vision correction procedures that can free you of the hassle of wearing glasses or contacts.
