Cat eye drainage

A feral cat that I care for has green drainage coming from both eyes and they are swollen. I’m not sure I’ll be able to catch him to take him to a vet. Will this go away on its own?

Hello!  I'm afraid that it may be unlikely to disappear by itself.  I wonder about all kinds of things from chronic cat 'flu to foreign bodies, entropion, dry eye and so on, but all except the merest bit of green 'sleep' at the inner corner of a normal-looking eye, would likely need medical attention. You have a decision to make: do you consider this cat to be yours?  If so, it needs to be scanned for a chip to verify that it isn't someone else's legal property and then, assuming it isn't, to be registered to you.  You would then be responsible for your cats' health-care. If you are not / do not wish to become the owner, the cat needs to be handed in as a stray for treatment as appropriate.  There are charities who might take this on,  but you would probably not be reunited afterwards. Whatever you decide, swollen eyes discharging green may be classed as emergencies; your vet will help you to triage the situation and aid you in making a decision. Best of luck with this dilemma and please let us know how you get on.