Contact lenses may be a very popular and successful way of correcting the vision of patients who suffer from refractive eye errors such as near-sightedness or far-sightedness, but this doesn’t make them suitable for everyone. In fact, there are several different demographics of patients that are unable to wear regular contact lenses. Fortunately, there is a solution -scleral lenses. Scleral lenses are a variety of specialty contact lens, designed specifically for those patients for whom standard contact lenses are not a viable option.
Standard contact lenses make consistent contact with the cornea across the entire lens. Scleral lenses do not. Instead, they vault over the surface of the cornea and instead only make contact with an area of the sclera – which is the white of the eye. Exactly where your scleral lenses will make contact with the sclera will depend on the size of the contacts that you choose:
Semi-scleral lenses are the smallest type of scleral lens and first, make contact with the eye at the point where the cornea meets the sclera. Despite being the smallest variety of scleral lenses, they are still significantly larger than regular contacts.
Mini scleral lenses are slightly larger, making contact with the interior of the sclera.
Full scleral lenses are the largest type of scleral lens, making contact with the sclera but also having the largest clearance between the cornea and lens.
Scleral lenses vault over the top of the cornea, leaving a clear gap between the cornea and the back of the contact lens. This gap is the core element of the design of scleral lenses and is important for several reasons.
Scleral lenses have a significant clearance between the corneal surface and the back of the contact lens. They are also made from gas-permeable material. Scleral lenses have been specifically designed this way so that:
Plenty of oxygen can reach the eyes.
The gap acts as a reservoir for tear film, keeping the eyes moist.
There is enough space between the cornea and lens for any abnormalities.
Scleral contact lenses are much, much larger than regular contacts. Regular contacts are usually between 8-10mm in diameter. Meanwhile, scleral lenses can range from 14-20mm in diameter. This means that patients are afforded better coverage, greater stability, and easier handling, as well as scleral lenses, being better suited to people with specific conditions.
As we know, scleral lenses have been designed specifically for people that are unable to wear conventional contacts. There are various types of patients who are considered good candidates for scleral lenses. These include:
Patients with dry eye disease. Dry eye disease occurs when the patient is unable to produce enough natural tear film, the tear film drains too quickly, or the tear film is poor quality and doesn’t provide enough lubrication. There can be many reasons why this happens, from environmental factors to taking certain medications. The gap between the lens and the eye afforded by scleral lenses acts as a reservoir for tear film, reducing symptoms of dry eye in those patients who may not be able to wear regular contacts because of their condition.
Patients with an irregular cornea. The cornea is usually domed fairly evenly. However, some patients may have a much steeper cornea that is more conical in shape. This can make it difficult or impossible for contact lenses to fit properly and comfortably and remain stable. Since the lenses of scleral contacts vault over the cornea, they are less likely to be affected by abnormalities of shape.
Patients with ocular surface diseases. There are a number of different ocular surface diseases, and these can make it difficult for patients to wear regular contact lenses. Scleral lenses can provide a barrier that protects the compromised anterior ocular surface from exposure and is generally considered more suitable for patients with ocular surface diseases.
If you’d like to find out if you are a good candidate for scleral contact lenses, please get in touch with TMS Eyecare in Wichita, Arkansas City KS today.