Your eyeglass prescription is a set of numbers and abbreviations your optician turns into lenses. This guide walks through what each value means — from OD and OS to SPH, CYL, AXIS, ADD and PD — so you can read your prescription with confidence.
Your eyeglass prescription can look confusing at first, with abbreviations, plus and minus signs, and numbers that aren't immediately clear. Each part of your prescription tells your optician how to make lenses that correct your vision.
A better understanding of these numbers can help you feel more informed when choosing new glasses or discussing changes in your vision with your eye doctor.
Common Vision Problems That Require Prescription Glasses
Eyeglass prescriptions correct refractive errors, which occur when light doesn't focus properly on the retina at the back of your eye. These conditions can affect how clearly you see at different distances.
Nearsightedness (Myopia)
Myopia makes distant objects appear blurry while nearby objects usually remain clear. It occurs when light focuses in front of the retina rather than directly on it.
Farsightedness (Hyperopia)
Hyperopia can make nearby objects difficult to focus on, although distance vision may also be affected. Some people experience headaches or eye strain, particularly during reading or other close-up activities.
Astigmatism
Astigmatism occurs when the cornea or lens has an uneven curvature, causing blurry or distorted vision at near and far distances. It can occur alongside nearsightedness or farsightedness.
Presbyopia
Presbyopia is an age-related change in the eye's ability to focus on nearby objects. It typically becomes noticeable after age 40 and may make it harder to read small print or view your phone.
Unlike hyperopia, presbyopia develops as the eye's natural lens becomes less flexible with age. Reading glasses, bifocals, or progressive lenses can help correct near vision.
