Lisa V Davis OD (Philadelphia,PA 19149)

• Are UV levels in the high mountain higher than in the lowland?

  Yes, you will be exposed to more UV rays when in the mountain. The UV rays will increase by 6% to 10% when the altitude increase 1000 meters. So you should have full protection when climbing mountain.

• Why is Anti-reflective coating applied to the back surface of sunglass lenses?

  AR coating is applied only to the back surface of sunglass lenses because there are no cosmetic or visual benefits to eliminating reflections from the front surface of dark-tinted lenses. It eliminates glare from sunlight reflecting into your eyes from the back surface of tinted lenses when the sun is behind you.

• Do sunglasses with 100% UV protection are much more expensive than other sunglasses?

  No. That whether sunglasses have 100% UV protection has nothing to do with the cost. Some cheap sunglasses which are labelled with 100% UV protection can also give you 100% protection from UV rays. So when you choose sunglasses, just check the label to see whether they have 100% UV protection.

• Can anyone know the symptoms of presbyopia?

  The early sign of presbyopia is that you can't see close up things such as reading. If you are over 40, it is possibly that you have got presbyopia. Other symptoms include eyestrain, headaches or feeling tired from doing up-close work.

• How can I get free eye exam?

  If you are U.S. citizens and legal residents, you can get free eye exam from EyeCare America which is a public service program of the Foundation of the American Academy of Ophthalmology.

• How to choose proper lens according to different prescription?

  Your prescription is not so strong. People who have prescription strength from -300 to -500 can choose the 1.56 to 1.59 lens, which can fit your power properly.

• Do sunglasses in dark tinted color give more UV protection than the light color?

  No, the UV protection has nothing to do with the tinted color. Dark sunglasses can only offer you a mild view when in bright light but they don't absorb more UV rays.

• Why can't we have monovision in our glasses?

  There is no need to use monovision glasses because the progressive glasses enable us to see both near and far. You will have much more satisfactory vision with progressive lenses or even bifocals.

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