I'm Sorry to hear. It would be easier for me to answer if I knew how big your aquarium is and if you have a filter and heater? If you have a filter then he shouldn't be having a hard time breathing but if he is then I would suggest turning up the water flow for more oxygen. It could also be that your tank is to dirty and you need to clean it more offen for more Oxygen for your puffer to breath. I am not sure about the blindness. Sorry. But maybe your light is to strong and if that doesn't work I would turn off your light and see what happens when its off.
I hope your puffer lives and nothing happens.
Hope this helps.
