In the 60¡¯s to 70¡¯s, frame selection was a purely mechanical consideration almost entirely dominated by the optician and his subjective judgments. Today the cosmetic factor is predominant. The variety of frame color, materials, and style means that the main burden of selection has passed to the customer, leaving the optician control a subtle factor often difficult to exert. Common materials include nickel silver, Hi-nickel alloy, bronze, stainless steel, gold, gold plated, gold clad, copper beryllium, titanium and sometimes aluminium. In manufacturing of metal frames with the materials, even though fashion is the stimulant of consumer demand, all the metal frame for the prescription to refractive correction should be designed correctly styled eyewear which is cosmetically pleasing, functional correct, physically comfortable, mechanically and structually perfectible, and temperamentally acceptable.
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