When the input is 80V you are running the opto isolators at more than 10mA , which is far more than they need. I suggest you increase the 2k2 resistors to 4K7 or 10K. If you do rewire the PCB to put the LEDs in series with the opto isolators, then this will make the LEDs less bright, but unless you view them in direct sunlight they should still be bright enough, especially if they are green ones.