Prescription Sunglass Lenses for Aviator Sunglasses
There are 4 basic types of vision correction prescription lenses:
Each prescription lens corrects a specific defect in your vision. The correction required determines how thick the lens will be whether you choose CR-39Â® plastic, polycarbonate or glass material for the prescription sunglass lenses. Let's discuss vision correction.
How Single Vision Lenses Work
Single vision prescription lenses have one correction, normally it's the distance correction, but you can also have the lenses made just for reading or computer use. If you do not tell your eye examiner anything different, he will measure your distant vision for a focus at "infinity" of about 10 feet or more. You can also have reading or computer lenses made, just tell the examiner how many inches or feet away you need to focus at.
How Bifocal Lenses Work
Bifocal lenses have two corrections, the upper part of the lens is set for "infinity", or distant use, the lower part of the lens (the segment) is set to focus close up for reading which is normally about 15-18 inches. With the normal "flat top" bifocal lens when you move your eye from the top part of the lens (the distance correction) to the lower reading (bifocal segment correction) you change the focal point of your eyes from "infinity" down to about 15 to 18 inches. Your prescription will have the bifocal part listed as the "add", for example +1.50. When you order bifocal sunglass lenses from us you should tell us where the top of the bifocal segment to be. Normally it would line up with your lower eyelid.
How Trifocal Lenses Work
Trifocal lenses have three corrections where the upper part of the lens is distance correction, the smaller 7mm to 12mm segment is the intermediate correction that focuses at about 24 to 36 inches, and the lower bifocal segment of the lenses focuses at about 12 to 18 inches, just like a regular bifocal. A note about trifocal lenses: there is not choice of power on the part of the reading segment. If the doctor prescribes lets say a +2.00 for the bifocal part, which is the lower part, the upper segment will always be 50% of the bifocal. In this example the +2.00 bifocal will have a +1.00 intermediate power. The +2.00 will focus 12 to 18 inches and the +1.00 intermediate part will focus at 24 to 36 inches.
Multi focal Vision
How Multifocal Lenses Work
Multi focal lenses, sometimes called "no lines" or "PALS" (Progressive Addition Lenses), or just Progressive lenses, are the "state of the art" for people who need more than three fixed focal lengths. This is the most sophisticated multi-focal lens available, and has the greatest focal range, most nearly approaching natural vision. The invisible reading segment is a narrow verticle channel that starts out at the middle of the lens with a distance focal point, and gradually focuses up closer and closer until at the bottom of the lens it will focus down to about 10 to 12 inches. The best part of this lens is that it does not have fixed focus steps like flat top trifocals, it will provide a continuous focal point all the way down from infinity to about 10 inche. So no matter what you look at you can find a spot in the lens that will get you in focus. You just have to tilt your head up and down until you find the part of the lens that produces the best focus for what you are looking at.
Prescription Aviator Sunglasses
We provide prescription aviator sunglasses with your prescription. To get your very own prescription aviator sunglasses is a 3 step process:
- Get your prescription from your optometrist and email it to us;
- Purchase the aviator sunglasses frame you want;
- Purchase the prescription sunglass lenses you want.
We will do the rest. The whole process will take 2-3 weeks. Have a prosperous day!
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