ALERT

We accept walk-ins at most designated COVID-19 sites during vaccination days and hours. You may still schedule your vaccination or walk up to our mobile vaccination clinic which is open to everyone! Note: we require masks in all St. Luke's facilities, regardless of COVID-19 vaccination status. This helps us provide safe care in a safe environment for all patients. Access more info on COVID testing, vaccination, visitor policy, safety practices, hospitalization data, and FAQs.

toggle mobile menu Menu
toggle search menu

Site Navigation

Supplemental

Menu

Eyeglass Prescriptions

Eyeglass Prescriptions

Topic Overview

Prescriptions for glasses have two main components: shape and power.

The shape of a lens determines the type of correction.

  • Concave, or minus, spherical lenses are thicker at the sides than in the middle to correct nearsightedness (myopia).
  • Convex, or plus, lenses are thicker in the middle than at the sides to correct farsightedness (hyperopia) or presbyopia.
  • Cylindrical (toric) lenses are curved more in one direction than another to make up for irregularities in the cornea that cause astigmatism.
  • Convex lenses or bifocals refocus the image on the retina when people with presbyopia lose the ability to focus on close objects around age 40.

The power of a lens determines the amount of correction. It is specified in diopters. The higher the number of diopters, the more vision correction the lens provides.

Credits

Current as of: December 18, 2019

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Healthwise is a URAC accredited health web site content provider. Privacy Policy. How this information was developed to help you make better health decisions.

© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.