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For eye care professionals

Eye-ruler 2 frequently asked questions

Find answers on our measurement App

Setting up


How do I install the Eye-Ruler 2?

Connect your compatible iPad to your internet, search Eye-Ruler 2 on the App store, click get and download the Eye-Ruler 2 App.

How do I log into the Eye-Ruler 2 App?

Contact Essilor’s marketing department and inform the Eye-Ruler 2 technical advisor of your Eye-Ruler 2 serial number, which can be found on the bottom of the Eye-Ruler 2 box. The technical advisor will set up your Eye-Ruler 2 and will inform you of your log in details.

How do I connect the Eye-Ruler 2 device to the Eye-Ruler 2 App?

Switch on your Bluetooth on your iPad, open the Eye-Ruler 2 App and switch on the device, a blue and green light will flash on the side of the device. Click on the settings button in the top right corner of the App and click Reset device pairing and wait until the battery icon in the bottom left corner of the App is filled white. Once the battery icon is filled your device is connected.



How do I measure a new patient?

Once your device is connected click on the new customer icon. Enter your patient’s prescription and details and click on measurements at the bottom of the App. You will now be able to start the Far Vision Personalised measurements, including the Near Vision Behaviour measurement.

Do I need to enter my full patient’s details?

It is advised to enter as much of the patient’s details when setting up a new patient so it is easier to find historic measurements and details and will also help with exporting measurements to e-Store.

I cannot take a measurement picture, what should I do?

Ensure that your patient is in a well lit area of your practice with minimal back lighting and their frame and clip are fitted correctly. Check that the iPad is held vertically so that the screen shows the clear camera image in the middle and that you are at the correct distance, and angle if on the second picture, and the measurements shown are in green. 

When my patient is taking the Near Vision Behaviour test the App keeps telling my patient to rotate the device, what should I do?

Check that your patient is sat in a well lit area of your practice with no back lighting and that their frame and clips are fitted correctly.  

When taking the measurement pictures the camera the patient’s cornea reflexes are not showing, what should I do?

Check that the device is correctly connected and that there is minimal back lighting behind the patient. Turn up the brightness on the brightness scale on the App when taking the measurement pictures. Retake the measurement pictures if necessary.

Will there be convergence issues with the patient’s PD measurements due to taking the measurement picture at the given distance?

The gaze axis being given by the clip, parallax is automatically corrected as head cape is reset at 0° by our algorithm. When adjusting the frame and clip for your patient ensure it is still in the gaze axis.




How do I charge the Eye-Ruler 2 device?

When the battery icon on the App is low connect the device to the magnetic USB charging cable provided and plug it into a USB adapter plug.

How do I take pictures of my patient in different frames?

Click on new or existing patients and click on frames at the bottom of the App. This will allow you take to up to four pictures of your patient so they can see the different frame options available.

Why is a stand not necessary for Eye-Ruler 2?

A stand is not mandatory for Eye-ruler 2 since the App takes into account iPad inclination. A measurement picture can be taken with - / + 5° inclination. The angle registered by the iPad inclinometer helps necessary adjustments to the pantoscopic tilt measurement. The calculation takes into account gaze as if it was perfectly horizontal which adjusts fitting heights as well. Other parameters wrap, PD, etc are not impacted by iPad inclination. It is the only iPad solution truly using a real 3D reconstruction.

How can I export the patient’s measurements to e-Store?

To export your patient’s measurements to e-Store you must first connect the App to the e-Store by going into the iPad settings, scrolling down to Eye-Ruler 2 towards the bottom on the left hand side and entering your e-Store log in details. You must enter esuk# in the username field followed by your username. You must enter your password for e-Store into the password field.

Once you have completed the patient’s measurements click on the export button, a square with an arrow pointing up, this will export the patient’s measurements to e-Store.

How can I print off my patient’s measurements?

If you have a wireless printer you can click on the printer icon after you have completed the patient’s measurements.