We're often asked what the prescription means. Here's the technical explanation.
The Sphere (Sph) This indicates the power of the lens that is needed to correct your sight.
A minus power ( - ) is prescribed if you are short sighted
A positive power (+) is prescribed if you are long sighted
The strength of lens is indicated by the numerical value; lens power is given in 0.25 steps, the higher the value the stronger then lens.
The Cylinder (Cyl): Cylinders or Cyls are prescribed to correct Astigmatism. Astigmatism relates to the shape of the front of the eyes, the eye can be shaped like a rugby ball as opposed to spherical like a football; the rugby ball shape can cause vision to be distorted. Cylinders help to correct astigmatism by providing further power across one area of the lens.
Axis: The axis is linked to the cyl as it indicates its position. It enables the cylinder to be placed in the correct position when the lens is mounted into a spectacle frame.
Near Vision Add: The near vision add is an amount of power which when added to the distance prescription will provide clear vision whilst looking at something within an arms length range.
Intermediate Add: The intermediate add is an amount of power which when added to the distance prescription will provide clear vision whilst looking at a mid range, a computer screen for example.
Prism: Prisms are prescribed to help the eye muscles and reduce the feeling of eye strain or double vision (if present). Prism helps the eyes to work together.
Base: The base is the direction that the prism will be placed when the lens is being made.
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