Reviewed by Universal Craftsman from RI on Tuesday, May 07, 2013
I have had this particular model of Native's before and really liked them. I jumped at the price and picked these up. When i got them i noticed they had a couple patches of ink like markings on either side of the lenses. Not a deal breaker but would have liked to know before hand that i was getting a "2nd" quality pair.
Base curve radius or simply base curve, abbreviated BCR or BC, is the measure of one important parameter of a lens in optometry. On a spectacle lens, it is the flatter curvature of the front surface and on a contact lens it is the curvature of the back surface. Typical values for a contact lens are from 8.0 to 10.0 mm. The base curve is the radius of the sphere of the back of the lens that the prescription describes. Contact lenses must fit well to the wearer's cornea in order to be comfortable and to facilitate tear exchange and oxygen transmission.
Answered on 7/23/2012 12:00:00 AM by Customer care from Sierra Trading Post