Jim, don't use the product used for CLEANING contact lenses. You can use the product labeled Sterile Saline Solution. I keep them in single-use ampules (I think our Walgreen's pharmacy brand)...8-10 strewn throughout my larger FAK and 2-3 in my pocket FAK.
There are some labeled for "sensitive eyes" or preservative free: they are usually free of the thimerosal preservative, or sorbic acid preservative, and are ph balanced. However, none on the U.S. market are just water and sodium chloride alone. They will have something else, e.g. sodium borate, etc.

From a practical standpoint however, there is no reason why you can't use them for irrigating a wound. In my experience actually treating an eye injury in the field (there was an Opthalmologist along on that trip) and also using the solution to irrigate other lacerations, we needed a larger volume of fluid than you would imagine. Ended up using drinking water, after all.