PRESCRIPTION
Your glasses prescription, explained in plain English.
A glasses prescription is a small table of numbers and abbreviations: OD, OS, SPH, CYL, AXIS, ADD, PD. Each one has a precise meaning, and once you know them, the whole paper reads in a few seconds.
Type your values into the tool below to see what they say about each eye, or read the guide underneath, one line at a time. The tool runs on your screen only: nothing you type is sent or saved.
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OD and OS: which eye is which
OD stands for oculus dexter, Latin for right eye. OS stands for oculus sinister, the left eye. Many prescriptions simply write R and L, or RE and LE. If you see OU, it means both eyes.
Each eye has its own line because the two eyes are rarely identical. A small difference between them is common.
SPH: the minus or plus sign says it all
SPH, the sphere, is the main power of the lens, measured in dioptres. A minus sign means you are short-sighted (myopia): distant things look blurry, close-up is clear. A plus sign means you are long-sighted (hyperopia): your eyes work harder to focus, especially up close.
The further the number is from zero, the stronger the correction. Values move in steps of 0.25, so -1.75 or +2.50 are normal, while -1.80 is not. Plano, PL or 0.00 means that eye needs no sphere correction at all.
CYL and AXIS: astigmatism
CYL, the cylinder, corrects astigmatism: an eye that is curved a little more in one direction than the other, so it focuses unevenly. If the CYL box is empty, or reads 0.00 or DS, that eye has no astigmatism to correct.
AXIS is always paired with the cylinder. It is not a strength but a direction, written in degrees from 1 to 180, and it tells the lab how to orient the correction in your frame. Some prescribers write the cylinder as a minus value, others as a plus value: both describe the same lens, and our optician converts one into the other before anything is cut.
ADD: extra power for reading, and progressive lenses
ADD, the addition, is extra plus power for close work, added on top of your distance correction. It usually appears from the mid forties, when the eye's own focusing for near starts to fade (presbyopia). It is often written once for both eyes, between +0.75 and +3.50.
At FrameLens, a prescription with an ADD is made as progressive lenses, also called multifocal or varifocal: one lens that covers far at the top, the middle distance in the corridor, and near at the bottom, with no visible line.
PD: pupillary distance
PD is the distance between the centres of your pupils, in millimetres, typically between 54 and 74 for adults. It is used to place the optical centre of each lens exactly in front of each eye. It can be one number, like 63, or two halves, like 31.5/32, one for each eye.
Many prescriptions do not show a PD at all. That is common and not a problem: the centring of your lenses is part of our optician's work, and first-time progressive wearers are measured in person with the frame on their face.
What we need to make your lenses
A clear photo of your prescription is enough: SPH for both eyes, CYL and AXIS if there is astigmatism, and the ADD if there is one. Our system reads the photo, and a licensed optician checks every value before a single lens is cut. If a number is unclear, we ask you rather than guess.
We fit lenses to the prescription you already have. Whether it still matches your eyes is a question for your optometrist or ophthalmologist: FrameLens does not examine eyes or write prescriptions.
QUESTIONS, ANSWERED
What does a minus sign mean on my prescription?
A minus sign in front of the SPH value means short sight (myopia): your lenses help you see far away. A plus sign means long sight (hyperopia). The bigger the number after the sign, the stronger the lens. A minus sign in the CYL column is simply a way of writing astigmatism and does not mean short sight on its own.
Is my prescription still valid?
Neither this tool nor our team can tell you that: we explain and fit what is written, we do not examine eyes. Many eye care professionals suggest a check every one to two years, and sooner for children or if your vision has changed. If you are unsure, any eye clinic in Dubai can check your eyes and issue an up-to-date prescription.
Can you use my prescription from another optician?
Yes. A prescription from any optometrist or ophthalmologist, in Dubai or abroad, works as long as the values are readable. Upload a photo when you order, and a licensed optician verifies every value before cutting. If something is unclear, we contact you before going further.
What does PD mean?
PD means pupillary distance: the space between the centres of your pupils, in millimetres. It is used to centre each lens in front of your eye. If your prescription does not show it, that is normal: we take it from your previous pair of glasses, or we measure you when you drop your glasses at our atelier.
Can I use my contact lens prescription for glasses?
No. A contact lens prescription is written for a lens that sits on the eye, so its powers can differ from a glasses prescription, and it carries extra values such as base curve (BC) and diameter (DIA). For glasses, use the prescription written for spectacles.