My cat is losing weight and eye is swollen?

ok having had many cats myself and one now that loves to fight.i have two suggestions.firstly is it conjunctivitis, if it is use strong salty water (one teaspoon of salt to about 60/80 ml of water)and fully dissolve it and clean out eye with a strong tissue or something that isn't going to leave the cloth in their eyes if it breaks. bath 3 times aday and try to keep your cat inside.ok if it looks more serious than this then your cat my have an infection some where on its face.try to feel for any lumps or sores around the area that is swollen.if u find a lump that has a sore on top of it its a good chance you have just found the infection(prob caused by fighting).I just had this happen to my cat and the vet wanted 200 bucks to fix and i couldn't afford.so my solution was to first make up a batch of very salty water,and get some antiseptic(dettol) or something of the kind,and lots of tissues.find the sore that is infected then if you can cut a little bit of hair back around it,then if you can get someone to hold our cat you will first have to pull the sore apart to start releasing the puss then with your fore finger and thumbs on both hands place them around the wound and start squeezing squeeze until blood starts to come from wound and then bath with salt water and apply antiseptic.you may have to repeat this process for 2 /4 days until a nice scab has formed.if it isn't any of these things i would take to vet as it has probably been hit by a car and need more urgent attention.i hope ur pussycat gets better