To care for vintage cat eye glasses all you need to do is clean them on a regular basis with warm soapy water (use a gentle non abrasive soap) and then rinse clean. Dry them off with a soft dry cloth. You can use eye glass cleaner on the lenses too if you prefer and wipe clean with a soft dry cloth.
Cat eye glasses are like any other type of glasses and can scratch easily. To prevent scratching your glasses put them in an eye glasses case when you are not wearing them and use a soft cloth when wiping them clean. Always be careful how you handle them so that you do not drop them. Also use both hands when putting them on, so as not to bend the frames out of shape.
Vintage glasses of this kind are to be handled with care because of their age. They are sensitive to extreme heat so make sure not to leave them on the dashboard of your car in a sunny parking lot on a hot summer day as this can cause the plastic to dry out and shorten the life of your frames. Also, check the screws on the side of your glasses to make sure that they are tightened, in order to maintain a proper fit. Do a routine check on your vintage glasses so that you know they stay in great condition.