Warning
Author is not responsible for consequences of your usage of this script for your eyes, vision and health. You can use it at your own risk or probably have a consultation with a doctor first.
When reading a book for some time eyes can become tired.
The one reason of that can be that eyes are looking inward, and the muscles are strained.
This script duplicates content of every PDF page making the page wider, so both eyes can look at theirs own content without muscles strain for looking inward - eyes are in position like when they are looking at something at the distance.
Usually the distance between the pupils is around 6-7 centimeters. Thus make sure that the distance between left and right contents of the generated pages has the same size on the gadget screen. Usually E-reader or smartphone in horizontal orientation can be adjusted to make this proportion. There are also some parameters in the script that can help.
generate_pdf(file_name, postfix="_binocular", crop_v=0, crop_h=0, gap=0)
file_name - PDF file path
postfix - string postfix that will be added to resulted PDF file name
crop_v - crop page on top and bottom
crop_h - crop page on left and right sides
gap - crop interval between two initial pages on one PDF page
Some PDF books can have wide paddings on left/right or top/bottom, to reduce them,
crop_v and crop_h parameters can be used.
Also gap parameter can be used to reduce or increase gap between left/right contents on the page.
Install pypdf
pip install pypdf
Update PDF file name in the script and run it.