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Contact Lens Types |
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Most Popular Lenses |
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Contact Lens Brands |
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| How to Read Your Contact Lens Prescription |
- Your contact lens prescription contains several pieces of information that are needed in order to correctly
dispense contact lenses. At a minimum, the prescription will contain the following:
- Power - this is the strength of the contact lenses. The numbers may be negative (if you are short-sighted) or positive (if you are near-sighted).
The numbers are measured un units called diopters (D) and are usually given in quarter steps.
For example, -4.25D. The larger the number the stronger the prescription.
- Base Curve (BC) - This number relates to the curvature of your eye. The higher the number, the flatter your eye surface. Base curve values
usually range from about 8.0 up to 9.5. However, most lenses are available in only two base curves, and some contact lenses are
only available in a single base curve.
- Diameter - This is a measure of the overall size of the lens, and for soft lenses, the diameter ranges from about 13.0 to about 15.0 mm.
Most lenses are only available in a single diameter. If you don't see the diameter listed in the shopping cart for your lens, don't worry, this means that
there is only one diameter for this lens
- Brand - The contact lens brand your doctor has prescribed.
- Expiration - Your doctor will usually write an expiration date for your prescription. In most states, this will be one year
from the date of your contact lens fitting. In some states, the expiration is two years. Federal law prohibits your doctor
from writing a shorter expiration on your prescription unless there are documented medical reasons for doing so.
- Toric (Astigmatism Correcting) Contact Lenses - If you wear this type of lens, your prescription will contain two additional
pieces of information i) Cylinder (measured in Diopters) and axis (measured in degrees) which determine the amount and alignment of your astigmatism
- Right (OD) and Left (OS) Eyes - The prescription will typically have two lines - one for the right eye, one for the left. In most cases,
the prescription will be different in each case. The right eye is usually called OD, and the left OS. If you happen to have the
same prescription in each eye, your presacription will just have a single line referenced as OU.
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