Hard Contacts

Rigid gas permeable contacts, more commonly referred to as hard contacts, are made of a special plastic material that permits the transfer of oxygen through the lens. Hard lenses were introduced in the late 1970s as an alternative to contact lenses made of Polymethylmethacrylate (PMMA), a plastic material that did not allow the passage of oxygen through the lens. Today, the popularity if gas permeable contacts has declined in favor of soft contacts, but for certain patients, hard contacts may provide clearer vision and more convenience when compared to soft lenses.

Oxygen transport to the eye is important as a lack of oxygen to the cornea, the transparent front of the eye, can result in heavy swelling, which severely impacts vision. Contrary to intuition, rigid contacts actually allow more oxygen to reach the surface of the eye when compared to soft contact lenses. This can be an important consideration for patients with sensitive eyes. Many patients also find hard contacts to be more comfortable in the long run. Initially, there is a training period for hard lenses where the patient’s eyes gradually adjust to the presence of the lenses. After wearing the contacts for several days, however, most people are able to wear the contacts continuously without discomfort. Because the hard lens material does not contain water like soft lenses, users will be less affected by foreign particles in the eye and will experience fewer problems related to drying of the lenses. For patients experiencing keratoconus and certain types of astigmatism, soft contacts are not able to correct vision problems and rigid lenses are required. Finally, whereas the most durable soft contact lenses need to be replaced after a few months, hard contacts will last for several years given the necessary care.

Although gas permeable lenses are much less common than soft lenses, hard contacts can provide a number of important benefits for wearers.