Osika John OD (Scottsdale,AZ 85255)

• Why does my vision go completely black for a few seconds?

  I often have such problem. It usually happens when I wake up or stand up suddenly. My doctor said it was because Low blood pressure or Low blood sugar. You may see the doctor to find the real cause.

• 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.

• What's the difference between polycarbonate lenses and Trivex Lenses?

  Polycarbonate lenses are available in a wider variety of lens designs than Trivex lenses. Trivex lenses have a higher Abbe value and may produce sharper peripheral vision with less chromatic aberration than polycarbonate lenses. Trivex lenses have less internal stress and may produce sharper central vision than polycarbonate lenses.

• 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.

• 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.

• What should I apply when cleaning glasses with anti-reflective Lenses?

  You should not use the regular detergent liquid as the harsh chemical may damage the anti-reflective coating. There are some special cleaner safe for anti-reflective coating you can get at the optical store or use only products that your optician recommends.

• 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.

• 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.

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