Prescriptions Explained

What does my prescription mean?

Your prescription is the most important thing about your glasses. It is the power that you need to be able to see. It is individual to you, and we operate strictly within British Standards Tolerances to ensure that we handle it with care and make your glasses exactly correct for you. There will be two sections, for your left and right eyes. If you cannot read it clearly to enter it online, you can scan it and e-mail it, or fax it to us.

The distance prescription allows you to see for walking around, driving, and television. If you are under the age of forty you will be able to do everything in this prescription.

The intermediate prescription is used for the VDU, or maybe reading music. It is a weaker version of your reading prescription.

The reading prescriptionusually develops after the age of forty (See Presbyopia in Information) and is used for reading, sewing, and all close work.

On your prescription form, it will look like this but obviously the values would refer to your eyes:

your prescription explained

Sphere or SPH Power

This will be a + or – sign followed by a number, which changes in steps of 0.25. Please be careful when entering the prescription, that the plus or minus sign is correct. It may be written down without the decimal point in the middle, i.e. 200 not 2.00 All prescriptions will have the Sphere part filled in. If we feel that your prescription does not ring true, we will contact you! In the sphere space it may say ∞.This means zero, or infinity, or plano, and simply means there is no power. On our order, enter plano or infinity.

Cylinder or Cyl Power

Not all prescriptions will have this part, or you may only have it in one eye. It is written in a similar way to the sph above, again it will be plus or minus. This corrects astigmatism in your eye, a common defect. (see Astigmatism for more information)

Axis

This will only be filled in if you have a cyl part to your prescription, and is a number between 0 and 180.

Add

This is what we need to add to the Sphere value to enable you to see to read. It is the Addition or near Addition. It may be written across the whole row of boxes as one value, as it will be the same in both eyes. The optician may however add it to the distance prescription for you, in which case it will read similarly to the top, distance row.

Prisms

Prisms are sometimes necessary to make vision comfortable. They have a value plus a direction, i.e. 4 base out. Just enter this on the order form. Usually the prism value is shared between both eyes, so it will be on the left and right eye.

Base

This will only be filled in if you need a prism in your prescription – see prism above. Base refers to the direction of your prism, it will say IN, OUT, UP or DOWN.

Balance Lens

The Optician uses this term if you have no vision in that eye, so the lens power is irrelevant. He just wants the glasses to have a suitable lens which balances the weight, to make the glasses feel comfortable and look as good as possible. If he has written balance but also written a prescription power down too, just give us all the information and we will sort the order out for you.

If anything else is written on the prescription form or you do not understand it, then contact us. A qualified Optician will deal with your enquiry.