By aitkineyeca32139567, Jul 14 2020 01:54PM
Glasses and contact lens prescriptions are not the same. They are similar, but have significant differences and are not interchangeable.
Glasses prescriptions are based on a refraction to determine the “power” of the eyes. The doctor determines the amount of myopia (near-sighted), hyperopia (far-sighted), and astigmatism to provide the clearest vision. The doctor will also specify if a bifocal, or reading power, is necessary. The glasses prescription may also specify “prism.” Prism is additional power ground into the lens to help the eyes work together as a team to reduce double vision and eyestrain. A glasses prescription is typically finalized during a comprehensive eye exam.
Contact lens prescriptions not only take into account the refractive power of the eyes but also the health of the eyes while wearing the contact lenses. Therefore a contact lens prescription also includes the material of the lens, the diameter of the lens, and the base curve of the lens. A poorly fitting contact lens, a lens material that dries out, or a material that does not allow enough oxygen to your cornea may result in discomfort or something more serious like vision threatening eye infections. Two brands of contact lenses with the same “power” are not the same and are not interchangeable because they may fit differently and have different effects on the health of your eyes. To finalize a contact lens prescription the doctor needs to observe the contact lenses on the eyes and assess the vision and determine the effect of the contact lenses on the eyes. Many times this requires a separate appointment.
Glasses and contact lens are 2 options to see clearly, but the prescriptions are not the same.