Why Your Glasses and Contact Lens Prescription Are Not the Same

Wear glasses? Wear contacts? Both help your vision, but did you know, each have different prescriptions? If you’ve been to the eye doctor and been fitted for both, you’ll notice you get a prescription for each. That’s because your glasses and contact lenses are positioned differently. Glasses are about 12 millimeters from your eyes and contact lenses, are of course on your eye.


Both glasses and contact lenses include a power to correct your vision, whether you’re nearsighted or farsighted. If you choose contact lenses while at your doctor’s office, he or she will also perform a contact lens exam. When your doctor fits you for contact lenses they’re determining the base curve measurement. This measures the curve of your cornea. On your prescription you’ll see it labeled as BC. Another measurement you’ll see on your prescription for contact lenses is called the lens diameter (DIA). The DIA is the size of the contact lens from side to side.


Whether you wear glasses, contact lenses, both, or don’t need them, getting a comprehensive eye exam is important to your overall health. When doctors in the VSP individual plan doctor network conduct an exam, it’ll always be a complete WellVision Exam that not only determines your prescription, but also checks for issues like hypertension, diabetes or other health symptoms. If you need vision insurance you can learn more about individual vision plans here.