More than 24 million people in the United States wear contact lenses, keeps in mind the University of Michigan’s Kellogg Eye Center. Contact lens tests are different than evaluations for glasses. During a contact examination, the eye is determined and other tests are done to determine the best type and fit of contact lenses.
Average Eye Measurement for Contact Lenses
There is a wide range in the numbers in contact prescriptions, but some measurements have an average in the power, curve and size of the contact lenses.
Power of Contacts
Power is the strength of the contact lens, the part that amplifies and assists proper vision. Inning accordance with the Ohio State University Medical Center, although contact lenses resemble a phenomenon prescription, contact lens measurements typically have different numbers. Power is written as a system of measurement called a diopter. Diopters can range from 0.00 to 20.00 and be composed as a plus number or a minus number. Plus is for farsighted and minus is for nearsighted. The typical number for both far and nearsighted is 3.00. The extra numbers often include the curve and size of a contact lens, but may contain other details as well.
Base Curve of Contacts
The base curve, or BC, is the radius of the back of the contact lens, the part that rests on your eye. Inning accordance with Laser Eye Surgery Review, the typical measurement of a base curve is in between 8.0 and 10.0. An example of a common base curve would be BC 8.7 mm.
Size of Contact Lense
All contact lenses have a measurement called the size. This measurement is in millimeters and is the size of the lens. The August, 2005 problem of “Contact Lens Spectrum” keeps in mind that the typical contact lens size is 14.0 mm.
Expiration Date of Contacts
Contact lenses are thought about a medical device and much like prescriptions for medications, contact lens prescriptions expire. The measurements of the eye modification and need to be upgraded with eye assessments each to two years. The majority of physicians write an expiration date of one year on a contact lens prescription.
Factors to consider
The Federal Trade Commission implements the Contact Lens and Eyeglass Rules, a law that offers patients the right to have a copy of their contact lens and glasses prescription. Optometrist need to provide patients a copy of their last prescription for glasses and contact lenses.