How to Read Your Child’s Eye Prescription (Quick & Easy Guide)

First time reading your child’s glasses prescription? No sweat. We’ll break it down step by step so it actually makes sense.

1. OD and OS – Which Eye Is Which?

· OD (Oculus Dexter) = Right eye

· OS (Oculus Sinister) = Left eye
When you open that prescription sheet, OD is the top row or the right-eye column, and OS is the left. If both eyes are same, you might see OU (both eyes)

2. SPH = Sphere: Nearsighted or Farsighted?

· SPH stands for Sphere.

· A minus (-) before the number means nearsighted (myopia), like -2.00 D.

· A plus (+) means farsighted (hyperopia), like +1.50 D.
Bigger numbers = stronger prescription

3. CYL and Axis = Astigmatism Info

· CYL tells you how much astigmatism correction is needed.

· Axis (0–180°) gives the angle direction for the correction.
If CYL is blank or says “DS,” it means no astigmatism is present

4. ADD & Prism (Sometimes Included)

· ADD is for reading or bifocal needs—usually not in kids unless they need special lenses.

· Prism helps correct double vision or eye alignment issues—not common in most children

5. PD = Pupillary Distance

· PD measures the distance between your child’s pupils.

· It ensures that the optical center of the lenses lines up correctly in the frames.

· You might see one number (e.g. 56 mm) or separate monocular PD like 28/27

Why This Matters for Kids

Knowing how to read your child’s prescription means:

· You can enter the prescription correctly when ordering glasses online.

· You can ask informed questions to the optometrist if anything changes.

· You ensure your child’s glasses are made accurately, giving them clear, comfortable vision.

Parental Tips

· Keep the prescription sheet safe—update it after each eye exam.

· Check that OD/OS values match what the eye doctor last told you.

· Ask about PD if it’s missing—you’ll need it when ordering frames.

· If values are small, kids may not complain—but glasses still help reduce eye strain and support healthy vision development

Bottom Line

Reading your child’s eye prescription is easier than it looks. Once you know what each abbreviation means—OD/OS, SPH, CYL, Axis, ADD, Prism, PD—you can confidently order glasses, track changes over time, or talk to the optometrist if something seems off. It’s a small step that helps your child see clearly and comfortably every day.