I would be very careful feeding cut grass they will eat it a lot quicker than they would if they were grazing and could cause bloat especially if her system is already compromised from having treatment for her eye.
I would buy a bale of hay and feed that, far safer. I had a lamb penned up for 10 days a couple of months back due to a joint infection and she just ate hay and creep with her friend that I bought in for company.