ADD stands for the added magnifying power in diopters in portions of the lens to help with seeing up close. And if you wear toric lenses your prescription will contain abbreviations like CYL and Axis.
This is the amount of power needed to correct your astigmatism. Axis expresses the orientation of the cylinder value on the lens. Contact lens brand s or material must be specified on a contact lens prescription because each lens material has a specific degree of oxygen permeability. This is especially important if you want extended wear contact lenses or you occasionally fall asleep while wearing your contacts.
Generally, a contact lens Rx is valid for one year. You will need to revisit your eye doctor when your prescription expires for a checkup of the health of your eyes before you can purchase additional lenses. Eyeglass prescriptions are regulated under state law, and most expire after two years. If you're choosing to cosmetically enhance your eye color with your lenses, that information will also be on the prescription. In some cases, the prescription also includes how often to replace the lenses whether they are daily, weekly, monthly etc.
For yourself, the new year is a great time to touch base with your optometrist and get fitted for a fashionable new pair of glasses or a fresh pair of contacts. In , VisionWatch reported that million people all over the United States used some form of vision correction, and about 11 percent alternated between glasses and contacts. Ready for your yearly eye exam?
After your comprehensive eye exam, your eye care professional will explain the details of your prescription and offer tips on how to keep your eyes — behind glasses or contacts — healthy for years to come. A Patient Care Representative will be in touch within 24 business hours to confirm your appointment. Back to All Insights. A common query for contact lens wearers is whether you can convert your glasses prescription into a contact lens prescription.
Both contact lenses and glasses correct common refractive errors such as myopia short-sightedness , hyperopia long-sightedness , astigmatism which requires toric contact lenses and presbyopia which requires multifocal contact lenses.
Although your contact lens and glasses prescription may look similar, it does not mean they will give you the same visual acuity if you try to convert one to the other. A glasses prescription is not the same as a contact lens prescription. Glasses sit slightly away from your eyes and contact lenses sit directly over your eye, so two different tests and measurements are required.
Depending on the refractive error, the strength of lens required to correct it and the type of contact lens you need, the parameters specified on your glasses prescription may be significantly different from those on your contact lenses prescription.
Note: The glasses prescription left and the contact lens prescription right above are just samples. Yours may differ but should contain the same information. Note: not everything shown on the above table will necessarily be included on your prescription. The above is just an example of what could be found on your prescription and what will not be found on your prescription depending on whether you wear contact lenses or glasses. Contact lenses prescriptions include certain specifications that are not part of a glasses prescription, these include: Base curve : the base curve measures the curvature of the lens; it is determined by the actual shape of your eye and produces the right lens fitting.
Diameter : the lens diameter specifies the overall size of the lens. Along with the base curve, this determines how the lens fits on the eye. Lens material : in days gone by, glasses were made from actual glass, nowadays, most glasses are made of a lightweight plastic. Contact lenses on the other hand, are made from a range of hydrogels. These are split into hydrogel or silicone hydrogel contacts.
Those with sensitive or dry eyes generally do better with silicone hydrogel contact lenses as they allow a greater level of oxygen and hydration into the eye. A glasses prescription contains a sphere indicating the lens power, a cylinder indicating strength of any astigmatism if there is one stated and an axis showing the orientation of the cylinder. A contact lens prescription may also include an axis and cylinder if it is a toric lens for astigmatism, or an add if it is a multifocal lens, these are the only two measurements that can be found on both contact lenses and glasses prescriptions.
Because the spherical correction for the right eye is 4D or greater, and because toric soft lenses are typically available in 0.
The exact prescription can be determined only with diagnostic lens fitting by an eye care professional. For the left eye, it's possible that a spherical soft lens with a correction identical to the glasses prescription You are entitled to a copy of your contact lens prescription once it has been finalized.
The point at which your Rx is final is the decision of your eye care practitioner. In some cases this can occur after the diagnostic fitting.
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