The standard hard lens is the grandfather of all the modern contact lenses. It’s still quite popular, but advancements in the other types of contacts have caused hard-lens use to decline at a rate of 10 to 15 percent each year. Hard (or, to use more pleasant terms, “rigid” or “firm”) contact lenses are small, firm, plastic discs that rest on the cornea of the eye, cushioned by a layer of tears. The plastic from which conventional hard lenses are made is called PMMA (polymethyl methacrylate) and is similar to Lucite and Plexiglas. PMMA has an excellent optical quality and has been proven to be nontoxic, stable, and highly resistant to warpage.

Hard contact lenses are, relatively speaking, “old hat” by now. There are dozens and dozens of manufacturers who, by and large, offer the same product. Unlike soft lenses, hard lenses do not require the rigorous testing and Food and Drug Administration approval before they can be legally dispensed. “First quality” hard contact lenses merely have to follow the voluntary standards set up by the American National Standards Institute. Based on information gathered over several decades of hard contact lens use, these standards apply to the following lens properties: hardness, strength, flexibility, scratch resistance, resistance to impact, absorption of saline and distilled water, gas permeability, wetting angle, light transmission, heat distortion, and shelf life.