Possible Cataract. There are other possibilities, but regardless of the cause, your baby needs to be seen by an opthomologist right away.
Blocked tear duct. If you are describing a intermittent mucousy film over the eye then it is probably a result of a blocked tear duct (lacrimal stenosis). The tears can't drain from the eye and secretions build up and sometimes get infected. If the cornea seems cloudy this may be a more serious problem requiring the attention of an ophthalmologist.