On a different note... my son had visual processing problems when he was young. It was very difficult for him to read words on a page of text whether that be on paper or on computer. Changing the colour of the background helped some, but I cut out a piece of cardboard with a space in the middle the size of a line. That enabled him to read the words/lines without interference from all the other text on the page. When reading books we did the same idea with a ruler or with a piece of card, so that it just highlighted the one line at a time.

At one time his teachers even started using different coloured chalk on the board in class. Different colours for different sections instead of everything being in white chalk on a green or black background. e.g. blue for homework. green for math etc.. It worked a charm and not just for my son but for all the children.

Obviously he was very young and it's probably not very practical for you to do that but changing background colour can be very helpful.

So, highlighting makes a lot of sense. It's just a bit time consuming I would imagine.