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Scleral Lenses

By Gary Heiting, OD

If you've been told in the past that you cannot wear contact lenses because of an irregular cornea or other problems, you may want to get a second opinion and ask your eye doctor about scleral contact lenses.

Scleral contacts are large-diameter gas permeable contact lenses specially designed to vault over the entire corneal surface and rest on the "white" of the the eye (sclera). In doing so, scleral lenses replace the irregular cornea with a perfectly smooth optical surface to correct vision problems caused by keratoconus and other corneal irregularities.

Also, the space between the cornea and the back surface of scleral lenses acts as a fluid reservoir to provide comfort for severe dry eyes that otherwise could not tolerate contact lens wear.

Scleral lenses are noticeably larger than standard gas permeable contacts and have a diameter equal to or greater than that of soft contact lenses.

Types of Scleral Lenses

There are several types of scleral contact lenses, based on lens diameter. They are:

The average human cornea is approximately 11.8 millimeters in diameter, so even the smallest scleral lenses are designed to cover the entire corneal surface. In comparison, most conventional gas permeable (GP) contact lenses are 9.0 to 9.5 mm in diameter and cover only 75 to 80 percent of the cornea.

During your contact lens exam and fitting, your eye care professional will determine the best scleral lens type and size for your specific needs.

Scleral Contacts for Keratoconus

Many optometrists and ophthalmologists recommend scleral contact lenses for a variety of hard-to-fit eyes, including eyes with keratoconus.

In early cases of keratoconus, a standard GP lens may be used. However, if the lens does not center properly on the eye or moves excessively with blinks, causing discomfort, switching to a large-diameter scleral contact lens may solve the problem.

Because scleral lenses are designed to vault the corneal surface and rest on the less sensitive surface of the sclera, these lenses often are more comfortable for a person with keratoconus. Also, scleral lenses are designed to fit with little or no lens movement during blinks, making them more comfortable in many cases, compared with wearing standard gas permeable lenses.

Scleral Lenses for Other Eye Problems

In addition to keratoconus, scleral lenses are used for eyes that have undergone a cornea transplant, severe dry eyes caused by Sjogren's syndrome and other eye problems. And scleral bifocal contact lenses are available for the treatment of presbyopia.

Many eye doctors prefer to use the smallest scleral lenses possible to correct vision problems. Generally, smaller (corneo-scleral) lenses are easier for wearers to apply and remove than large, full scleral lenses.

Theatrical Scleral Contacts

Sometimes the term "scleral lenses" is used to describe theatrical contact lenses that dramatically alter the appearance of the wearer's eyes.

However, these special-effect contact lenses (also called costume contact lenses, Halloween contacts or gothic lenses), typically are soft lenses that bear little resemblance to scleral gas permeable contacts other than their large diameter to fully mask the cornea. Also, soft theatrical contacts usually are designed for cosmetic purposes only and not for vision correction.

Large-diameter scleral and semi-scleral GP lenses rest on the sclera and vault over the misshapen cornea in keratoconus.

Scleral Contact Lens Cost

Scleral contact lenses are custom designed for each wearer, so fitting scleral contacts demands greater expertise and more time than fitting standard soft or GP contact lenses.

Often, computerized maps of the curvature of the entire cornea are generated to facilitate the fitting process, and several trial lenses of different sizes and curvatures may be applied to the eye during the fitting process.

Also, depending on the type of vision problem and scleral lens size, your eye doctor may order one or more fenestrations (small, machined holes) to be placed in the periphery of your scleral lenses to adjust the fluid movement behind the lenses, which also affects how the lenses fit.

And it may take more time to help you master how to apply and remove scleral contacts, due to the larger size of the lenses.

For these reasons, scleral contact lenses cost significantly more than standard contacts; in fact, it is not uncommon for scleral contacts to cost three or four times more. In cases when a complex, highly customized scleral lens is required, cost can be as high as $4,000 per eye* or more.

Most insurance programs do not cover the full cost of scleral contact lenses, but in some cases vision insurance may reduce the cost of your lenses and/or fitting fee. Ask your eye doctor's office for details. Also, some eye care practitioners offer financing options for scleral contacts.

*Data on file.

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[Page updated February 2011]