COPD and eyesight

I over exert sometimes and now after practically suffocating Saturday I woke up Sunday and my eyesight is worse. The letters and numbers on my phone turn very light and a white cloud goes over what I’m reading. Why? This has happened for days at a time then a little better. I know I have a cataract. Does lack of oxygen to the brain affect sight? I’m at least advanced COPD my doctor said : years ago.