Obtain your prescription
Have you had an eye test, but your optician didn't provide your prescription because they were concerned you wouldn't buy their glasses?
The UK Opticians Act of 1989 stipulates that it is the responsibility of every optician to provide you with your prescription. The optician will conduct a comprehensive eye examination and, as required by law, provide you with a copy of your personal prescription.
Understand your prescription
Important tip - The most common misunderstanding!
One of the most common mistakes customers make is selecting the wrong "+" and "-" when entering their prescription online. We cannot emphasize enough how important it is to pay extra attention when choosing these values!
At first glance (especially for new wearers), your eyeglass prescription may seem very confusing, but it is actually quite easy to understand. Your prescription usually looks like this (depending on the country):
Let's see what these measurements mean.
SPH / Sphere
The sphere value indicates the strength of the lens required to correct your focus. A positive number corrects hyperopia (farsightedness - difficulty seeing close objects), while a negative number corrects myopia (nearsightedness - difficulty seeing distant objects).
The sphere value is measured in diopters. Your prescription might also include terms like "plano" or an "infinity" symbol, which means you are neither nearsighted nor farsighted, and your sphere value is zero. However, you may still have astigmatism, which will be indicated by "CYL" (cylinder) and "AXIS" on your prescription. Typically, the range for sphere values is between 0.00 and +/- 20.00, in increments of 0.25.
CYL / Cylinder
CYL (Cylinder) and AXIS values compensate for astigmatism. So, what is astigmatism? Astigmatism occurs when the shape of the eye is slightly like an oval (similar to an American football or torus) rather than a perfect sphere like a soccer ball. This means the eye has difficulty focusing at certain angles.
This field can be left blank or filled with positive or negative values. The unit of measurement is diopters. Typically, the range for cylinder values is between +/- 0.25 and +/- 4.00, in increments of 0.25.
AXIS
Only when there is a value in the CYL field does the AXIS field come into play. The AXIS indicates the orientation of the astigmatism in your eye. The unit of measurement is degrees. Typically, the range for axis values is between 0 and 180, in increments of 1, 5, or 10 degrees. We only display integer values for the axis, but if your prescription includes a fractional degree, you can specify this additional condition when placing your order.
ADD / Addition
ADD stands for reading addition, which is the additional magnifying power needed for reading. This value is reflected in reading glasses, bifocal lenses, or progressive lenses.
The ADD value indicates how much additional power is required for near or intermediate vision on top of the distance prescription at the top of the lens. This extra value is always the same for both eyes and may appear only once on your prescription. However, it applies to both eyes. The unit of measurement is diopters, and the typical range is between +0.50 and +3.50, in increments of 0.25.
The ADD power only appears if your glasses are intended for reading or close-up work. If your glasses are for distance vision only, this will not be an issue. Some opticians use "Add" or "Near" to indicate the reading addition. Even if it appears only once on your prescription, it applies to both eyes and is consistent for both (e.g., 'Add' +2.50 - applies to both eyes).
Pupillary Distance (PD)
Pupillary distance is the distance between your pupils, ensuring that the prescription lenses are centered correctly in front of your eyes.
The most common method for measuring PD uses a simple PD ruler. Typically, the optician holds the PD ruler between their thumb and index finger, using the other three fingers to stabilize the patient's head. The optician then closes their right eye and instructs the patient to look at their open left eye, aligning the zero mark of the ruler with the patient's right iris edge. The optician then closes their left eye, opens their right eye, and instructs the patient to look at their open right eye. The value that aligns with the patient's left iris edge is the PD.
For adults, PD usually ranges from 60 to 66mm (see diagram). While 63mm is a common PD, we recommend obtaining this measurement from your optician or an existing pair of frames. Alternatively, You can also measure your PD using the following method:
1. Stand about 20cm (8 inches) from a mirror.
1. Stand about 20cm (8 inches) from a mirror.
2. Hold a ruler against your forehead, aligned horizontally.
3. Close your right eye and align the 0mm mark with the center of your left pupil.
4. Open your right eye, close your left eye, and read the measurement at the center of your right pupil.
5. Repeat a few times for consistency.
Tips for accurate measurement:
- Wear your glasses: If you normally wear glasses, wear them during the measurement to ensure accurate results.
- Take multiple measurements: For added accuracy, take multiple measurements and average the results.
- Consult Your Eye Care Professional: If you're unsure about your PD or have any questions, consult your eye care professional.
When placing your order, please don't forget to enter your PD information. This is necessary for ensuring the correct alignment of your lenses.