By Dr. Itua Enakhe (OD)
Decoding your glasses prescription is easier than it seems. This guide explains the key elements of a prescription, including sphere, cylinder, axis, and more, helping you understand your vision correction needs. At SpecSMART Eye Clinic Ikeja, expert opticians provide precision eye care and personalized guidance for your perfect eyewear.
1. What Is a Glasses Prescription?
A glasses prescription is a written order from an optometrist or ophthalmologist after an eye exam that details the corrective lenses you need. It includes lens strength, measurements for fitting, and corrections for conditions like astigmatism. At SpecSMART Eye Clinic Ikeja, optometrists ensure each prescription is tailored through a thorough vision assessment
2. Decoding the Prescription
a. Right and Left Eye
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OD (Oculus Dexter): Right Eye
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OS (Oculus Sinister): Left Eye
b. Sphere (SPH)
Indicates nearsightedness or farsightedness, measured in diopters (D).
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Negative number (-): Nearsighted (myopia)
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Positive number (+): Farsighted (hyperopia)
Example: -
SPH -2.00 = myopia of 2 diopters
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SPH +2.50 = hyperopia of 2.5 diopters
c. Cylinder (CYL)
Corrects astigmatism caused by an uneven cornea shape. This number may be positive or negative.
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CYL -1.25 = astigmatism correction
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CYL 0 or blank = no astigmatism
d. Axis
Number between 1 and 180 that shows the orientation of the astigmatism correction in degrees. Only present if CYL is specified.
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Axis 90: Correction placed vertically
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Axis 180: Correction placed horizontally
e. Add (Near Vision Addition)
Additional magnifying power for close-up vision, common in presbyopia (age-related near vision difficulty).
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Add +2.00 means +2.00 diopters added for reading or close tasks
f. Pupillary Distance (PD)
Distance in millimeters between pupils, essential for proper lens alignment. Often measured separately during exams.
g. Prism
Used for eye misalignment corrections (e.g., strabismus), measured in prism diopters (PD) with a direction (base-up, base-down, base-left, base-right).
3. Sample Glasses Prescription Explained
| Eye | SPH | CYL | Axis | Add | PD |
|---|---|---|---|---|---|
| OD | -2.50 | -1.00 | 180 | +2.00 | 63mm |
| OS | -1.75 | -0.75 | 90 |
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Right eye (OD): Nearsighted with some astigmatism, axis at 180°.
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Left eye (OS): Nearsighted with less astigmatism, axis at 90°.
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Add +2.00 for near vision (reading glasses).
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PD is 63 mm for lens alignment.
4. Choosing the Right Glasses at SpecSMART Eye Clinic Ikeja
After understanding your prescription, our opticians help you choose suitable lenses and frames, from single vision to multifocal lenses. We ensure a comfortable fit and accurate prescription application for optimal vision and style.
FAQs
How often should I get an eye exam?
Every 1–2 years or as recommended by your optometrist for updated prescriptions and eye health.
What if I have astigmatism?
Your prescription will include a CYL and Axis number to correct it precisely.
What does Add mean in my prescription?
Add refers to extra magnification for close-up tasks, often needed for presbyopia.
Why is PD important?
PD ensures lenses align with your eyes for clear and comfortable vision.
Can I get multifocal lenses with my prescription?
Yes, SpecSMART opticians specialize in bifocal and progressive lenses for combined vision needs.
📍Contact SpecSMART Eye Clinic Ikeja
Ile-Oja Mall, Opebi Link Road, Ikeja.
📞 0703 839 1197