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Contact Lenses
Fitting Contact Lenses
Contact Lens Prescriptions
Contact Lens Complications
Caring for Contact Lenses
Contact Lens Prescriptions
For the untrained eye, prescription contact lenses can be very
confusing. There are only a few simple details one needs to
understand in order to understand what their prescription
means.
A prescription will look something like this.
OD -6.40 -2.00 90 +1.10
OS -7.00 -1.00 180 +1.00
BC 8.6 DIA 14.2
Follow the legend below:
OD is for the right eye
OS is for the left eye
OU refers to both eyes
The first number (-6.40) refers to the refractive
power. It is measured in diopters.
A negative value indicates myopia
A positive value indicates hyperopia
The number indicates the amount. The farther from zero the
number, the greater the amount.
The second number (-2.00) indicates the amount of
astigmatism (if any exists). It is measured in diopters.
Astigmatism is present if the shape of your eye is like a
football, as opposed to a sphere.
The third number (90) is a measurement of the axis of
astigmatism in degrees. An axis of 180 is horizontal. An axis
of 90 is vertical.
The last number on the top line (+1.10) indicates
reading power (if any exists) for a bifocal lens.
BC is the base curve (radius) of a contact lens. It is
measured in millimeters.
DIA is the diameter, measured in millimeters.
Consumers should be wary about
buying contact lenses without a prescription. Only
nonprescription lenses should be purchased without a contact
lenses prescription. It is important to understand your
prescription contacts so that you can ensure that you are
getting the product you require to meet your vision
requirements.
ALERT!
The FDA has alerted consumers about
potentially serious side effects associated with wearing
special effects contact lenses. The U.S. Food and
Drug Administration's Center for Devices and Radiological
Health has advice for consumers wishing to
purchase contact lenses on the Internet.
The National Eye Institute (A
Division of the National Institutes of Health) offers
excellent resources about
vision, eye
care and contact lenses. This site is available in
both English and Spanish. The Optometrists Network
provides detailed information for parents about
children and vision care.
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