If you have distance glasses, wear them. It makes life much easier if your vision without them is acceptable but "borderline".
If you find the letters merge, just read what you see as it doesn't matter if they're out of order. Dyslexics are catered for, so it's only important to identify the digits, rather than get them in the right order. If you're having trouble verbalising, you may copy down what you see on a piece of paper.
Finally, don't worry about the difference between letter O and number zero, they're both the same and the examiner will accept either. Same with I and 1. Errors between M and W may be accepted on the first attempt if you're standing further away than the legal distance, but if the examiner gets the tape measure out on the 4th and final attempt, it has to be correct.