Is it okay to use restasis and cromolyn eye drops ?

The restasis can decrease inflammation blocking tear flow and therefor help eye dryness. Cromolyn attenuates allergy which is a completely separate issue. You can take both of these concurrently although wait a couple of minutes between each drop.

These two medications treat different things. Restasis is cyclosporine which reduces inflammation and facilitates natural tear production which treats Dry Eye Syndrome. Cromolyn is a mast cell stabilizer which treats allergy symptoms and some non-infectious conjunctivitis. You can use both concurrently but they treat different things.