Every patient has different visual needs and different prescriptions, so contact lenses should be custom fit and prescribed to suit each person's individual situation. Some patients have high astigmatism or corneal abnormalities which mean that conventional lenses won’t sit consistently or comfortably on the surface of their eyes, while others suffer from other eye conditions that result in discomfort or blur with conventional contact lenses.
As you may have guessed from the name, specialty contact lenses are contacts that are designed for patients who are unable to wear conventional contact lenses.
Some of the patients that might benefit from specialty contact lenses include those who:
have extremely high nearsightness, farsightedness or astigmatism
have been diagnosed with dry eye syndrome
have corneal scarring
have been diagnosed with keratoconus, a condition characterized by the thinning and bulging of the cornea
have suffered an injury to the eye
suffer from a peripheral corneal thinning disorder
are intolerant to other types of lenses
After completing a comprehensive eye exam, Dr. Kubota will be able to tell you if you need specialty contact lenses and if so, which lenses would be best based on your individual requirements. Here are some of the main types of speciality contact lenses and who they are recommended for.
Also known as RGP lenses, these are made from a special rigid plastic material that allows oxygen to pass through them and reach the surface of the eyes. In a patient with an irregular cornea surface, the rigidity of RGP lenses provides the smooth surface shape that is needed to focus light clearly, so it minimizes the the distortion that some corneal abnormalities have and helps these patients enjoy sharper vision. Our corneas need oxygen to stay healthy so an RGP contact lens's ability to breathe keeps the cornea from becoming oxygen deprived. RGPs also do not need water to maintain their form or optics so they do not dry out they eyes and are easier to wear for patients who suffer from dry eyes.
Scleral contact lenses are very different from standard contact lenses. Conventional contact lenses are small enough to rest on a patient's cornea. Scleral lenses are much larger in diameter so the edges of the contact lens come in contact with the white part of the eye called the sclera rather than the cornea. Scleral lenses are also different in that they vault over the surface of the cornea rather than touching it, leaving a space between the front surface of the eye and the back of the contact lens. This makes scleral lenses a good choice for patients with dry eyes and corneal abnormalities, such as the bulge associated with keratoconus. They are made out of a rigid gas permeable material.
Limbal contact lenses are another type of specialty lens that falls between rigid gas-permeable lenses and scleral varieties in terms of their size. Their larger overall diameter helps to increase their stability on the surface of your eyes. They also offer minimal interference with the eyelids, which helps to ensure comfort and clarity of your vision.
Hybrid contact lenses are a combination of both soft and rigid gas-permeable contact lenses, giving patients the opportunity to enjoy the best parts of both designs. The middle part of hybrid lenses is made from gas-permeable material that lets oxygen pass through to the eyes. The gas-permeable part of the lens is more rigid, and this firmer center gives the lens greater stability and the patient enjoys enhanced clarity. The RGP center portion of the lens also helps to keep a better tear film layer between the cornea and the lens so the eye remains hydrated. Meanwhile, the outer edge of a hybrid lens is a soft lens skirt. This means that the patient enjoys the comfort of a soft lens and not the hard edges associated with RGP lenses that may be more difficult to get used to.
Some patients with extremely high nearsightedness, farsightedness or astigmatism are able to wear specialty custom-made soft contact lenses that are available in extra high powers. They are sometimes available in quarterly replacement, which means that the lenses can be replaced every three months. This is far better than having to deal with the discomfort of a single pair that is replaced annually.
For more information about specialty contact lenses, don’t hesitate to speak to Dr. Kubota and our dedicated eyecare team.