An introduction of contact lenses prescription
Currently, Americans living in any of the fifty states can buy contacts either from ECPs or other sources such as optical chains, warehouse clubs and online stores. This privilege originates from a legislation passed in 2004 that patients were entitled to obtain a copy of contacts prescription from ECPs without extra cost. This was available only in certain states before that time. This law profoundly separated lens fitting from lenses buying. You will never be forced to buy contacts from ECPs after getting fitted. Today, a contacts prescription is just like another medical product such as medicines and may provide more information than eyeglasses prescriptions. With a lens prescription, customers can buy disposable lenses regularly.
Contact lenses are medical devices
An accurate prescription is needed for buying contacts due to their medical attribute. Poorly fitting contact lenses made of unsuitable materials may cause discomfort, inflammation, swelling, and most severely, permanent vision loss. Sharing contacts may also bring dangerous infections. In U.S., optometrists, ophthalmologists and a portion of opticians are entitled to fit contact lenses. In the United States, opticians are not eye doctors and only a few states allow opticians to fit contact lenses.
Prescription update helps detect eye problems
Subtle eye problems may have developed even if you are still feeling good with your eyes and contacts. Some ophthalmologists have ever found eye problems during regular eye exams, so that you must update the prescription within a certain period, which is also listed by either federal law or state law. Typically, the valid term is one year. But most state laws set a longer period. Another point worth mentioning is that you can change your contacts size, material or design if you are diagnosed with a lens-related problem.
A contact lens prescription uses standard terms, abbreviations and measurements, which look like secret codes yet easy for recognition. Standard entries include PWR, BC, DIA, CYL, AXIS, ADD, COLOR and BRAND. PWR is the exact power of the lenses. BC represents base curve. This value ranges from 8.0 to 9.5. If there is no BC entry, this value is determined by the contacts brand. DIA is short for lens diameter. CYL (cylinder) and AXIS items can only be seen in a prescription of toric lenses for astigmatism correction. The ADD item indicates an add power that is needed by bifocal contact lenses.
Besides regular items, your prescription may also tell the recommended lens replacement interval. There are monthly contact lenses, weekly contacts and even daily disposable contacts. However, before making a final decision you should always check ECP instructions, rather than simply follow the product instructions. In conclusion, a contact lens prescription is not the same as an eyeglass prescription. Besides necessary items like lens power, a contacts prescription contains much more information.
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