How to keep the device at 30 cm (without face-recognition)

Instructions and recommendations on how to best keep your device without face-recognition at a 30 cm distance from your face whilst playing the OKKO Health app.

The OKKO Health app can be played on an iPhone 6S and up. However, not all of these devices have face-recognition built-in to its hardware, meaning it cannot detect how far your face is from the screen during gameplay.

In order for the OKKO Health app to collect accurate results about your eye health, we need to know that you are at a 30 cm (+/- 2cm) distance from the screen throughout the session. So, how can you ensure that you stay at 30cm?

Watch this short video to hear what our OKKO Health user testers recommend.

We recommend not try and estimate the distance. Instead, try one of the following options:

1. Use a cereal box!

For this method, you must have both hands free. We recommend using an eyepatch, but feel free to experiment! For example, placing a tissue or a sock underneath your glasses.

A. Make sure to check the length of your cereal box equates to 30cm using a ruler or tape measure. 

B. Place the cereal box face down on a flat surface, preferably a table or desk.

C. Sit comfortably alongside it and rest your chin at one of the short-sided ends of the box.

4. Affix your eye cover and hold your phone at the other end.

2. If you don’t have a cereal box

you can instead measure the 30 cm distance using a measuring tape.

A. Starting from the edge of the table, measure 30cm in a straight line towards the centre.

B. Make a mark at 30cm.

C. Place your chin on the edge of the table and hold the device by the mark. It may be worth using something comfortable to rest your chin on, that also positions your face slightly higher. 


Still having difficulties? Speak to your eye doctor or send us an email on