Can you upload a photo?
Is it like a white coating over the eye, or is there any fluffy white growth?
Cloudy eyes can be caused by water quality, but if you believe this ok, then maybe parasites or bacterial problems.
Try a salt dip - 15 to 25 grams of aquarium salt in one litre (take a litre of water from the tank) .... I would use the highest dose as mollies are very tolerant of salt and often do best in mild brackish water. Leave the fish in the solution for up to 15 minutes, but remove back to the tank if it starts to show signs of distress at any point. You can repeat this daily if required. This will eliminate some skin parasites.