Eyeglass prescription or Contact lenses prescription are not the not the same. They differ significantly because of their positioning. Glass lens is placed approximately 12 millimeters away from your eyes in order to focus the power of the lens properly to the eyes, whereas contact lens is placed or rested directly on the surface of your eyes. Most of the people assume that the prescription of contact lenses and eyeglasses are similar and create problems associated with their eyesight. If you find any vision problem, first you need to consult an eye specialist and then go for different eye tests to determine the right prescription of your precious eyes. The information that is provided on your prescription of eyeglasses or contacts varies merely. An eyeglass prescription is particularly for the purchase of your desired glasses only. It does not coincide with the information on contact lens prescription. Contact lenses can be obtained only through eye consultation and fitting. Know the differences between a contact lens and eyeglasses prescription.
Major Differences between a Contact Lens and Eyeglasses Prescription
As like an eyeglass prescription, a contact lens prescription includes the power of the lens, which is required mainly to correct your refractive errors such as hyperopia (farsightedness), myopia (nearsightedness) and astigmatism. Based on the degree of your refractive error and the suitable type of contacts that is prescribed, the power is measured in diopters and is specified on your contact lens prescription. It may be significantly different from your glasses prescription because of the best vision possibility. Usually, the contact lens prescription contains extra specifications when compared to glasses prescription. These specifications are determined only by an extensive contact lens examination and lens fitting. Here are the few specifications of lenses.
- Base Curve: It is also abbreviated as BC, and this measurement is the curvature of the back surface of your contact lens. The particular base curve is determined by the shape of the cornea and enhances a fitting that is not too tight or loose.
- Diameter: The lens diameter (DIA) signifies the overall size of the lens along with the base curve to determine the fitting of the lens. The diameter of the rigid gas permeable (GP) contact lens ranges from 8.5 to 9.5 mm, and the diameter of soft contact lenses range from 13.5 to 14.5 mm.
- Material or Lens Brand: The brand of the lens and the material should be specified on a contact lens prescription because each and every lens material has a particular degree of oxygen permeability for the existence of lens on the surface of eyes. This specification is crucial if you use extended wear contact lenses or if you fall asleep while you are with the contact lenses.
- Expiration Date: Generally the prescription of contact lens is valid for one year, and you need to revisit your eye care specialist once your prescription expires for a checkup of your eye health. The prescription of eyeglasses is regulated under the state law and most of these get expired after two years of duration.
- Distance: The power of the lens that is prescribed for you helps to see the distant objects clearly. Your ophthalmologist suggests your distance prescription based on your capability to read an eye chart with various testing lenses.
- Magnifying Power: The added magnifying power of bifocal contact lenses is expressed in diopters and is specified for reading and close-up An eyeglass also has added power that restores near vision for older people with presbyopia. Usually, add magnifying powers are same for both eyes and ranges from +0.75 D to +3.00D.
- Test: An eye test varies in case of contact lens prescription and eyeglass prescription. The eye examination for contact lens is more complicated when compared to eyeglasses because your optometrist requires the measurement of your eyes such as diameter, the curvature of your cornea and size of the lens. Based on those measurements, your doctor will prescribe you the right type of lenses that helps you to get rid of your vision impairment. In case of eyeglasses, your optometrist will measure the power of your vision and the amount of refractive correction you need it.
It is advisable that before you take a prescription of your contacts, you need to check out for detailed information that consists of material name, power, design, base curve and diameter. You need to go for several visits until you achieve the successful fitting of your lenses. Whether a contact lens may be used for vision correction or cosmetic purpose, it is a special medical device that enhances your eye health. Selling any kind of contact lens without the right prescription is considered as an illegal act. So obtain a correct order for your contact lens or eyeglasses and protect your eyes.