In a message dated 3/17/08 1:26:12 PM, jim@xxxxxxxxx writes: > Those lenses are optically > designed with a filter as part of the formula. > And in addition to the three colored filters, there is also a clear "filter" of optically flat glass that has to be used when the colored filters are not in use. Otherwise the optical design goes south. Best regards, David at the top of the Chesapeake Bay. ************** It's Tax Time! Get tips, forms, and advice on AOL Money & Finance. (http://money.aol.com/tax?NCID=aolprf00030000000001)