Smith Optics Help Center

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Tips for understanding and reading your prescription.

Single Vision
​
​Prescription Format:
  • Typically presented in a grid format with fields like OD, OS, SPH, CYL, etc.
  • Values may be entered digitally or handwritten by the doctor.

SPH and CYL:
  • Sphere (SPH):** Indicates lens power for nearsightedness (-) or farsightedness (+).
  • Cylinder (CYL):** Corrects astigmatism, with a (+) or (-) sign.

​PD (Pupillary Distance):
  • Measured in millimeters (mm).
  • Can be a single number (e.g., 64) or two numbers (e.g., 31/33).
  • Important for aligning lenses correctly in front of each eye.

Progressive Lenses
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​ADD (Addition):
  • Applies magnifying power for near vision.
  • Always noted with a (+) sign.
  • Designations like DV (Distance Vision) and NV (Near Vision) may be specified.

Understanding Specific Entries

PLANO/PL under SPH:
  • Indicates no correction needed for nearsighted or farsighted vision.
  • Enter 0.00 in the SPH section of the Rx wizard.

SPHERE/SPH/S/DS under CYL:
  • Indicates no correction needed for astigmatism.
  • Enter 0.00 in the CYL section of the Rx wizard.

Multiple ADD Values:
If your prescription lists multiple ADD values, enter the one with PAL (Progressive Add Lens) into the ADD section of the wizard.

​OD and OS

OD (Oculus Dexter) and OS (Oculus Sinister):
  • Latin terms for right eye (OD) and left eye (OS).
  • Also seen as O.D. and O.S. respectively.
  • OU may reference both eyes, and RE and LE may also be used.

Additional Details
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​Ax (Axis):
  • Specifies the angle for astigmatism correction (1 to 180 degrees).
  • Always accompanies CYL if listed in the prescription.

Prism:
  • Corrects double vision or vision displacement.
  • Unfortunately, we cannot accommodate prescriptions requiring Prism corrections.

Measuring PD (Pupillary Distance):
  • Measures the distance between your pupils.
  • Obtain the most accurate PD by visiting your doctor or using tools like AccuPD.
  • Two-number PD (e.g., 31/33) is preferable for custom-made eyewear.