This is not good news. It is likely that your kitten has an upper respiratory infection which affects its eyes as well. This is usually caused by a virus and a secondary bacterial infection which then causes pus which "glues" the eye shut. Your kitty will need to be seen by a veterinarian ASAP, who will give her an exam to find out the cause and then prescribe medications accordingly, DO not wait for this to get better by itself, as the earlier the disease is treated the faster Lily La La will recover, Make sure she eats and drinks well.