Hard Contact Lenses
Hard contact lenses are made from glass and hard plastics. They provide vision correction for most types of vision problems. Glass contacts, PMMA contacts and RGP contacts are the three main types of hard contact lenses.
Glass contacts were the first hard contact lens developed. They could not be tolerated for long periods of time and are no longer prescribed. PMMA (polymethyl metacrylate), or Plexiglas, lenses were developed to replace the glass lens. They were lighter but still uncomfortable. Plexiglas lenses caused corneal damage due to decrease oxygen flow. They are still available but rarely prescribed. Rigid Gas Permeable (RGP) lenses are the most prescribed hard contact lens today.
Rigid gas permeable lenses are made of a hard material that allows increased oxygen flow as compared to the PMMA lens. Therefore it avoids the corneal damage caused by its predecessor. RGP lenses offer many other benefits to the contact lens wearer.
ADVANTAGES OF RIGID GAS PERMEABLE LENSES
DISADVANTAGES OF RIGID GS PERMEABLE LENSES
Rigid Gas Permeable lenses are equal if not better than soft contact lenses but thye are much less popular because they are usually uncomfortable to wear. Speak with your optometrist to determine what is best for you.