Eye protection

I have a question regarding the application or software that would control the playback of the video (let's say children's YouTube) .... when approaching less than 30 cm to the eyes, the video would pause or the screen would fade out, when the screen moved away more than 30 cm, the video would play again. Is this possible or is this idea already implemented??? If not, then you can help me to implement it. As I found out, some say. that you can't take control of products from Google, but you can create an extension for Google. Isn't it…..? And are there any sensors built into the phones that allow you to determine the distance to the face ... or will it be necessary to develop a separate device.