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

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

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.