If you want to purchase prescription eyeglasses online then make sure you understand one or two essentials before you start. It is possible to save a vast quantity of cash if you acknowledge how to buy your glasses wisely and it they will be perfectly sound for you to use so long as you become aware of a few simple rules
Make sure that they fit you properly
If your current spectacles fit o.k., then just measure them up properly and you will acquire perfectly fitting new spectacles online.
You need to know a few measurings:
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Of these the most important measurement is the total width (A). Providing you have go the accurate total width, it doesn’t really matter if you have not got the height or width of your lens to get your online eyeglasses to be a good fit.
Ensure that you have the proper lens prescription
There are merely a few parameters of your eye prescription that you will need to make a note of:
- Sphere - This refers to how short or long sighted you are. It is a measure of your lens optical power and is measured in diopters. It invariably has a addition (+) or a negative (-) sign in front or above it.
- Axis - this relates to the reference point which denotes the direction of the power of your lens. It only really applies if you have cylindrical lens though.. It relates to a factor between 1 and 180.
- Cylinder - This refers to the degree of astigmatism that you possess. Once Again, there is always a plus (+) or minus (-) sign present. There may not be a value of cylinder in your prescription.
- Pupillary Distance (PD) - This measurement is used to accurately center the lenses in the frame that you have selected. PD is the distance from the center of the pupil (black circle) in one eye to the center of the pupil in the other eye.
