Measuring your pupil distance
Within the UK, the PD measurement
is classed as a dispensing measurement as opposed to being part of the actual prescription of the person whose eyes were actually tested, therefore there is no obligation by law for a PD
to be provided to the patient.
It's always worth asking your optician for your pupillary distance when having your eye test completed, but as previously mentioned it is not a legal requirement for them to provide it and occasionally some opticians will refuse. Don't worry though it's a simple process to measure it.
We want you to be 100% happy with your purchase from us and an incorrect P.D measurement
, especially in higher or complex prescriptions, could make them uncomfortable to wear, cause headaches and potentially in extreme cases damage your eyes.
If your optician is not obliging though, all is not lost. Dont worry! - It is easy to measure it for yourself, just ask a friend to hold a millimetre rule just above the centre of your eyes and measure the distance between your pupil
centres. Both of you should be at the same height approximately, sat opposite each other. This can sometimes be tricky with large pupils or dark coloured eyes, another method it to measure the outside edge of one pupil to the inside edge of the other pupil, as shown in the picture below. Working in good light will also make measuring easier as the pupils will be less dilated.
The measurer holds the ruler in their left hand across the bridge of your nose and closes their LEFT eye to avoid any parallax error. With their RIGHT eye open, they then first line up the ruler with outside edge of your left pupil
. Then without moving the ruler they close their RIGHT eye and with their LEFT eye read off the measurement to the inside edge of RIGHT pupil. (See diagram)
You should fix on an object. E.g. the open eye of the measurer. This should ideally be about 40 centimetres, 16 inch (400mm) away.
This measurement will ensure the accuracy of your spectacle lenses when supplied.
A typical measurement
will usually be somewhere between 55mm and 72mm, with an average measurement of a medium built adult being 64 (We use this measurement if none other is supplied)