Do preparations before purchasing progressive eyelgasses
Compare to other eyeglasses, progressive glasses are a little expensive, especially in shopping mall or local optical store. Lucky, there is another way make our shopping easier, the most important is the cheaper price. Purchasing on virtual store has been the main approach to get our ideal items, the some sense does progressive glasses.
But before you order your eyeglasses online, you should do some preparations at the beginning time.
Measure your frame size and PD
The first step is the measure you PD which short for monocular papillary distance and it the distance from the center of a person bridge to the focal point of each eye, it isn’t always the center of the pupil. A light relax pupilometer is best used for that because it make a reflection on the actual focal point of the eye. That is to get the precise horizontal placement of the optical centers of the lenses. That is the PD
Then the height is simply measured with a ruler in millimeters from the inside bottom edge of the frame up to the center of the pupil of each eye. I have always found it best to back off 1 mm after, even though all progressives are ” supposed ” to be measured to the center. There are very often variations in the measurements between the two eyes in both PD and height, so each eye has to be carefully measured which is precisely why an online site can’t guess at the right height and get it correct. You can take a specific frame and measure the height on 5 different people with it, and get 5 different results., because the persons nose will determine how high or low their eyes will be centered in that frame.
Right prescription
Provide your current prescription which should get from you eyes doctors, a completely of prescription should contain your Sphere (to see far) and Cylinder (to see near) as well as Add (according to individual cases, not the necessary), make them correctly and match well with your current vision demands.
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