Contact lenses make it easier for people with poor vision to work and carry out daily tasks. About 45 million people in the U.S. use them to correct their vision.
Soft contact lenses are the same size as your corneas and lie on them. Scleral contact lenses are hard and larger than your cornea. They rest on the sclera, the whites of your eyes. Being gas permeable, they allow oxygen to reach your cornea and are better for eye health. They give better vision and can be used for longer periods. They're valuable if you can't wear regular contact lenses due to an irregular corneal shape or a disease.
What Are Scleral Contact Lenses?
The two common types of contact lenses are hard and soft. Hard lenses are often gas permeable, letting oxygen reach your cornea. Scleral contact lenses are larger than soft contact lenses. They're firm, hold their shape, and rest on the sclera around the cornea.
Like other contact lenses, scleral contact lenses correct poor vision caused by refractive errors. They can correct:
- Nearsightedness (myopia)
- Farsightedness (hyperopia)
- Distorted vision (astigmatism)
- Difficulty with near vision with age (presbyopia)
Scleral contact lenses are made of gas-permeable material. They allow oxygen to pass through to your cornea. Scleral lenses are valuable if your corneas are abnormally shaped, as in astigmatism and keratoconus. You can also use scleral lenses after LASIK (laser in-situ keratomileusis), a type of surgery to correct refractive errors, or corneal transplants. The space between the scleral lens and the eye is a reservoir that you fill with saline. Scleral lenses are comfortable for people with dry eyes.
Disadvantages of Scleral Contact Lenses
Scleral lenses are valuable for people who can't use other types. But they have a few disadvantages:
- Not every optometrist and ophthalmologist provides them. These lenses need special training.
- Scleral lenses are four to five times as expensive as soft contact lenses. But they can be used for much longer.
- Scleral lenses often collect debris and need cleaning during the day.
- They sometimes slip from their position.
- Getting used to scleral lenses after using soft lenses can be bothersome.
Scleral Lenses vs. Contact Lenses
Soft contact lenses rest on the cornea. They're soft, and most people find them comfortable to wear. But these contact lenses can be uncomfortable for people with dry eye disease, Stevens-Johnson syndrome, Sjogren's syndrome, keratoconus (abnormally shaped cornea), and graft-versus-host disease. People who have had corneal surgery may also be unable to use regular contact lenses.
Scleral contact lenses are larger than the cornea. Most are 14 to 24 millimeters in diameter. They vault over the cornea and rest on the sclera, the tough, white part of the eye. The fluid within keeps the eyes moist for longer.
Scleral lenses are not new. Their advantages in terms of oxygen supply to the cornea have been known for decades. They prevent hypoxic damage to the cornea and may also reverse damage that occurred previously.
Contact Solution for Scleral Lenses
You should always use specific solutions meant for contact lens storage and care. Never use water or any detergent solution for your contact lenses. Multipurpose contact lens solution can be used for cleaning and disinfecting your scleral contact lenses. These solutions also condition your lenses. You should replace your storage case every three months.
Other lens cleaning solutions contain hydrogen peroxide. These solutions also clean and disinfect your lenses. They also break up and remove trapped debris, protein, and fatty deposits. Hydrogen peroxide can damage your eyes. You must use a neutralizer that makes it safe to put your lenses into your eyes. A neutralizer is always sold as part of hydrogen peroxide lens cleaning kits. Leave your contact lenses in the neutralizer solution for at least six hours.
How Do You Put in Scleral Contact Lenses?
The process for putting in scleral lenses is different from that for soft lenses. Your scleral lenses have a reservoir to hold fluid and keep your cornea moist. These steps are needed:
- Wash your hands well with soap and water.
- Fill the lens well with a preservative-free saline solution. Preservatives can damage your cornea.
- Make sure there are no bubbles in the lenses, as these will blur your vision.
- When the lens well is full, place the lens in your eye using the three-finger tripod method.
Gas Permeable Contact Lenses
Gas permeable contact lenses are made of a material that holds shape but allows oxygen to pass through. Compared to soft lenses, about two to four times more oxygen is available to your corneas. They're smaller than regular contact lenses and cover about three-quarters of the cornea. They're made of a rigid material and hold their shape in use.
These lenses provide crisper, clearer vision than soft contact lenses. They're more durable and easier to handle. But you may need some time to get used to them. Their cleaning and disinfection process is more complex too.
Caring for Your Lenses
Your eyes are precious, and taking care of your lenses is important for keeping them healthy. Some important measures include:
- Wash your hands before putting in or removing your contact lenses.
- Always remove your lenses when sleeping. Wearing your lenses while sleeping carries an eight times higher risk of infection.
- Water can carry germs. Keep your lenses away from water. Never wear them while swimming or showering.
- Clean your lenses with a contact lens disinfecting solution.
- Clean your contact lens case with the same solution and change it every three months.
Caring for your lenses is vital for eye health. Improper care can cause diseases like keratitis and eye infections. If you have red eyes or your eyes are painful, remove your contact lenses immediately and talk to your doctor. Serious eye infections happen with contact lens use and can cause blindness.