Firmoo > Answers > Contacts >  question

Question

Ask questions

Dylan


04/30/2012

What is the difference between a contact lens prescription and glasses prescription?

I was asked to have an eye exam for contacts,but I just had one for my glasses.The doctor said they need the prescription for contacts.What is the difference between them?
Answer the question

Answers (4)

  • walkingrain

    05/21/2012

    This depends on how strong your power is. A contact lens prescription can be the same as a prescription for glasses when: - the prescription is a lower power, ie: -4.00 to +4.00 and - there is absolutely no astigmatism present. If you have any astigmatism or require a lens power greater than +/-4.00, the parameters of the contact lens can change. - if you have astigmatism under 0.50, a spherical lens should be prescribed. - astigmatism of 0.50 to 0.75 can be effectively corrected with an aspheric lens. - astigmatism greater than 1.00 should be managed with a toric lens. If your prescription power for glasses is greater than +/-4.00, you should see a difference in the power of your contact lens prescription. Generally, every time your glasses prescription increases or decreases by a power of 2, your contact lens prescription will increase by an additional power of +0.25. For every power change of 2 in a glasses prescription, the difference of +0.25 power is needed to compensate for the location of the contact lens. Your glasses are much further from the front surface of the cornea than contact lenses. Sources: https://www.contactlenses.co.uk/education/public/spectacle_vs_contact_lens_rx.htm
  • elbcoastboy

    04/30/2012

    Glasses prescription is usually stronger than that of contact lenses. Glasses are placed a little far away from our eyes while contact lenses are directly placed on our eyeballs. So they are much different.
  • Savannah

    04/30/2012

    The prescription on your contact lenses are greater than that on eyeglasses. Since eyeglasses are usually about 12 millimeters from the eye, the prescriptive power of a contact lens - which is positioned directly on the tear film of the eye - will be slightly less nearsighted.
  • Donny Mackaness

    07/11/2019

    Good morning I trust that this message finds you well. I have tried to contact you via email but it has bounced twice now so I am giving your contact form a go. I enjoy blogging in my spare time and I have written a couple of articles for your blog firmoo.com. Please find them attached on my Google drive: https://drive.google.com/drive/folders/1OzoW-WiFOlqrem86DV8YiasmDsiwMFtl?usp=sharing Do let me know what you think and do send me the links to the articles once you have managed to publish them. Also, do let me know if you would like me to write some more articles for your blog. Regards Journee
Jumpto