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Glossary of Eye Definitions and Glasses Terms
Want to discover all things eyewear? Find out more about your eyeglasses and sunglasses, word by word.
BackGlasses Axis
The glasses axis is the prescription value that indicates the lens meridian direction in which the lens provider should apply the cylindrical power to correct for astigmatism. The axis eye prescription describes the position of astigmatism but not the strength required for correcting the refractive error. The eye axis value ranges between 1 and 180 – a value of 90 indicates a vertical positioning of the vision correction and values closer to 1 or 180 indicate a horizontal positioning.
