Eyeglass vs. Contact Lens Prescriptions: Key Differences Explained

A prescription written for eyeglasses is different from a prescription for contact lenses due to the inherent nature of contact lenses.

FDA Classification

• The FDA classifies contact lenses differently from glasses because contacts are worn directly on the eyes, according to University of Iowa Health Care. There are risks associated with contacts that are not applicable with glasses.

Eyeglass Prescriptions

• An eyeglass prescription contains positive or negative numbers that denote the patient's level of farsightedness or nearsightedness. These refer to lens power. The prescription may also contain information about astigmatism.

Contact Lens Prescriptions

• In addition to lens power and degree of astigmatism, a contact lens prescription contains information regarding the size and fit of the lens, as well as the type, brand and tint of lens.

Distance

• The power of contact lens prescriptions must be adjusted for the difference in distance from the lens to the eye as compared to glasses.

Not Interchangeable

• A prescription for glasses generally cannot be interchanged with one for contacts and vice versa. Most doctors will require the specific prescription for the type of lenses you wish to obtain.