Buying glasses in Spain with a UK prescription

Your glasses break in January, halfway through the season in Mazarrón. Or you want prescription sunglasses for a summer that lasts half the year here. In the drawer you have the prescription from your usual optician, in English or in German, and the question is whether it is any use here.

It is. But it isn’t everything needed to make a pair of glasses, and it is worth knowing why.

Your prescription belongs to you

In the UK it is a legal requirement: after an eye test, the optometrist must give you your prescription, and the NHS points out that nobody is obliged to buy their glasses where they had the test. In Germany it usually comes in the Brillenpass or on the ophthalmologist’s prescription.

That piece of paper is yours. Any optician can read it, here included.

What a prescription tells you is how much correction each eye needs. What it doesn’t tell you is how those lenses have to sit in front of your eyes in a particular frame. That second part is measured at the optician’s, with the frame you have chosen, and it explains most of the glasses that “have the right prescription but I can’t see properly with them”.

How to read your prescription

The names change from country to country, but the information is the same.

• Right eye and left eye. R and L in English, R and L or OD and OS in German, OD and OI in Spanish.
• Sphere (SPH, Sphäre). The main prescription, in dioptres. A minus sign means short-sightedness; a plus sign, long-sightedness.
• Cylinder (CYL, Zylinder). Corrects astigmatism. If you have none, the box is left blank or says DS.
• Axis (AXIS, Achse). The orientation of the cylinder, in degrees from 0 to 180. No cylinder, no axis.
• Addition (ADD, Addition). What is added for close-up vision. It is the figure used for varifocals and reading glasses.
• Prism, if there is one. Uncommon, but it cannot be left out.

One thing that often causes confusion: visual acuity is not the prescription. In the UK it is written 6/6, in Germany Visus 1.0 and in Spain 1.0 or 10/10. It says how well you see with the correction on, not which lenses you wear.

The same prescription, written two ways

This is the detail that raises the most questions when comparing prescriptions from different countries.

The cylinder can be written with a plus sign or a minus sign, and both forms describe exactly the same lens. In Spain the minus cylinder is almost always used; elsewhere, depending on who writes it, you may see the plus form.

An example:

• +1.00 −0.50 × 90
• +0.50 +0.50 × 180

These are the same prescription. To go from one to the other you add the cylinder to the sphere, change the sign of the cylinder and turn the axis through 90 degrees. If one day you compare your old prescription with the new one and everything seems to have changed, it may be that only the way of writing it has.

What a prescription never includes

There are measurements no prescription carries, because they belong not to your eyes but to your eyes wearing a particular pair of glasses.

• The distance between your pupils. The NHS itself makes clear that the optometrist is not legally required to write it on the prescription: it is taken by whoever makes up your glasses. A couple of millimetres out is noticeable, and more so the stronger the prescription.
• The fitting height. In varifocals it decides where you look through for distance and where for reading. It depends on the frame, how it sits on your nose and your posture. It can only be measured with the chosen frame on.
• The distance from the eye and the tilt of the frame, which higher-end lenses take into account to sharpen vision towards the sides.

That is why varifocals made from the prescription alone, without those measurements, are the quickest route to feeling dizzy.

How long is a prescription valid?

It doesn’t expire like a medicine, but it does age. The NHS recommends an eye test every two years, or sooner if your optometrist advises it.

After 60 the prescription changes more often, and an eye test isn’t only about the prescription: it measures eye pressure and looks for signs that shouldn’t be missed. If your prescription is more than two years old, or you feel you no longer see as well with it, the sensible thing is to have it checked before paying for new glasses.

Some signs can’t wait for a check-up: sudden loss of vision, flashes or a curtain across your field of vision, eye pain or double vision that comes on suddenly. That is a matter for A&E, not the optician.

What to bring to the optician

• Your prescription, even if it is old. It is useful for comparison.
• Your current glasses. The lenses can be measured with an instrument called a focimeter to find out exactly what prescription they are, even if you have lost the paperwork.
• The glasses that have suited you best, if they aren’t your current ones. They say a lot about what works for you.
• What bothers you: reading, the computer, driving at night or the sun.

Who can make your glasses in Spain

In Spain prescription glasses can only be made in an authorised optical healthcare establishment, by a qualified óptico-optometrista. It is a healthcare profession regulated by law, and its duties include testing your sight, not only fitting the lenses, so it covers what in the UK would be split between the optometrist and the dispensing optician.

That means your prescription from home is a starting point, and here it can be checked or updated at the same visit.

At MODALENT we can see you in Spanish, English or German, in Puerto de Mazarrón. Bring your prescription and your glasses: we will go through them with you, explain what has changed if anything has, and take the measurements the prescription doesn’t include. This article is for information only and is no substitute for an eye examination.