Hard contact lenses are virtually obsolete today due to advances in contact lens technology. The old types of hard contact lenses were made from PMMA, or polymethylmethacrylate (also known as Plexiglas or Lucite). These lenses were durable and provided excellent vision, but they had major limitations.
What are hard contact lenses?
Hard contact lenses were introduced in the 1940s. Up until the 1970s, they were the standard contact lens of choice for most people with vision problems.
When soft contact lenses and gas permeable lenses were introduced, hard lenses quickly became obsolete. These lenses had a few major disadvantages, including:
Discomfort: Hard contacts were not considered very comfortable and it took a long time to get used to wearing them daily.
Risk of corneal swelling: Hard lenses were unable to transmit oxygen through the lens to the corneas. Without steady oxygen flow to the cornea, there is a risk of corneal swelling. The swelling could end up clouding vision and put people at risk of scratching their cornea.
Why are hard contact lenses used?
For a long time hard contact lenses were the only vision correction option available for people who did not want to wear glasses. Thousands of people wore hard contact lenses for years without experiencing any major problems. These lenses were extremely durable and did produce excellent visual results.
Benefits of hard contact lenses
Hard lenses may not have been extremely comfortable, but they did offer excellent vision correction results. One of the main issues with hard lenses was that many people experienced corneal complications from daily use. However, the cornea does tend to heal quickly; so many people had no issue with hard lenses and wore them successfully for years before making the transition to soft lenses or gas permeable lenses.