How to Read Your Prescription

Understanding Your Eye Prescription

Key Terms

• OD (Oculus Dexter) — Right eye
• OS (Oculus Sinister) — Left eye
• SPH (Sphere) — Lens power for nearsightedness (-) or farsightedness (+)
• CYL (Cylinder) — Lens power for astigmatism correction
• Axis — Angle of astigmatism correction (1-180°)
• ADD — Additional magnifying power for reading (progressive/bifocal lenses)
• PD — Pupillary distance in mm

Example Prescription

OD: SPH -2.50, CYL -0.75, Axis 180
OS: SPH -3.00, CYL -0.50, Axis 175
ADD: +2.00

Important Notes

Prescriptions are typically valid for 1-2 years. Always use a current prescription when ordering glasses.