Contact lenses have long been used as a popular alternative to wearing glasses for people who rely on prescription eyewear to see clearly. However, regular contact lenses aren’t suitable for everyone. This is primarily because the design of standard contact lenses means that they make contact with the entire surface of the cornea. Fortunately, the design of contact lenses has continued to evolve to enable there to be alternative options for patients who do not want to wear glasses but find it difficult to wear conventional contact lenses. This has resulted in the creation of scleral lenses.
Scleral lenses are just like regular contact lenses – only larger. Regular contact lenses are approximately 9-9.5mm in diameter, covering up to 80% of the cornea. They sit completely flat against the surface of the cornea, making it impossible for tear film and oxygen to circulate beneath them. It is this lack of tear film and oxygen that can make contact lenses impossible for people with dry eyes to wear.
In contrast, scleral lenses are much larger. The exact size of your scleral lenses will depend on the variety that you select. The smallest scleral lenses start at 14.5mm whilst the largest can be up to 24mm in diameter. They are also designed to vault over the corneal surface so that there is a space between the cornea and the back of the lens. This acts as a reservoir for tear film and enables oxygen to reach the eye, ensuring the lenses are comfortable to wear.
Just like all contact lenses, you will need a special appointment to determine the best scleral lens type and size for your individual requirements.
In the past, scleral lenses were only recommended for patients who had an irregular-shaped cornea. However, their use has expanded and now, any patient who has vision problems but who struggles to achieve clarity using glasses or conventional contact lenses may be considered to be a good candidate for scleral lenses.
Below are some of the conditions that can potentially be fully or partially treated with scleral lenses.
Keratoconus. Keratoconus is a condition affecting the cornea which causes the corneal tissue to bulge outwards in a cone shape, which makes conventional contact lenses unsuitable.
Dry eye syndrome. Dry eye syndrome is a fairly common condition, but it can make it difficult for patients to wear regular contact lenses. This is because the make contact across the entire surface of the lens, preventing tear film from flowing properly around the eye and causing it to feel dry, stiff and sometimes sore. Since scleral lenses have a space between the back surface of the lens and your cornea, tear film can flow more easily.
Sjogren’s syndrome. Sjogren’s syndrome is an immune disorder that causes patients to experience dry eyes, leading to complications with wearing contact lenses.
Corneal degeneration. As its name suggests, this refers to the degeneration of the corneal tissue, which can occur for a variety of reasons and can make it impossible for patients to achieve clear vision with regular contact lenses.
Exposure keratopathy. This condition is characterized by damage to the cornea due to the surface of the eye being exposed to the outside environment for excessive periods of time. Exposure keratopathy is linked to eyelid abnormalities, and both can cause issues with the distribution of tear film across the surface of the eyes, leading to dry eye syndrome.
If you would like more information about scleral lenses, or if you would like to schedule an appointment to discuss your candidacy for this solution, please get in touch by calling Federal Hill Eye Care in Baltimore, MD today.