Eyeglass prescriptions cannot be used for ordering contact lenses, or vice-versa.
There are two types of ophthalmic prescriptions based on the type of medical device (Eyeglasses or Contact Lenses) being ordered. All vision prescriptions generally offer the same type of vision corrections. The following prescription types are accepted for prescription orders.

Eyeglass Prescription
Note: OTC Readers do not require a verified eyeglass prescription.
A prescription lens strength for correction is prescribed for prescription lenses. The actual frame and lens option is generally selected by the wearer according to their preference and liking.
How to Read an Eyeglass Prescription

Contact Lens Prescription
A lens strength, along with the brand, wear duration, size, and curve of the contact lens is prescribed for contact lenses. Contact lens prescriptions are more complex than eyeglass prescriptions due to the fact the device (contact lens) comes in physical contact with the eyeball. A valid contact lens prescription is required even when ordering non-prescription contact lenses.
How to Read a Contact Lens Prescription