Does anyone know what is wrong with this chick eye and how to treat it

My friends chick has a swollen eye and it is grey and appears to be blind in the eye. The wing on the same side as the eye is wet like the chick has been rubbing it's eye on its wing to maybe scratch it's eye? Do you know what is wrong with it and how it could have got it and how to treat it and will the sight come back? Her other chicks are all healthy as are the mums. I have a photo I can add but dont know how to so if anyone can explain that I can get it up tomorrow.
The chick has been removed from the other chicks and mums and spent the day in her bath with water and food. It was happy enough but didnt move too much but did little chirp sentences when it was spoken to and did trott along to the voice okay. Now at night has been put in an incubator with some eggs incubating to keep it warm overnight. It did If it is some sort of disease would it transfer into the chick through the eggshell? Thanks for your help