Your prescription for glasses or contact lenses is a series of numbers in different boxes. Here’s an example:

The above prescription refers to someone with moderate short sight with mild astigmatism.

OD refers to your RIGHT eye prescription; OS to your LEFT.

The SPH (sphere) box shows how long- or short-sighted you are, measured in dioptres (D). The CYL (cylinder) box shows the strength of any astigmatism, also measured in dioptres. The AXIS box shows the position of the astigmatism on the eye, which is measured in degrees (°).

SHORT SIGHT is shown with a minus (-) sign, either before or above the value, in the SPH box.

LONG SIGHT is shown with a plus (+) sign, either before or above the value, in the SPH box.

ASTIGMATISM can be plus (+) or minus (-), and this is shown in the CYL box.

Remember that the final decision about your suitability for laser refractive treatment will always be made by an experienced Moorfields Private consultant who has examined your eyes thoroughly.