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 eye (sclera). In doing so, scleral lenses functionally 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 a scleral lens acts as a fluid reservoir to provide comfort for people with severe dry eyes who otherwise could not tolerate contact lens wear.
Scleral Contact Lenses For Keratoconus
Many optometrists and ophthalmologists recommend scleral contact lenses for a variety of hard-to-fit eyes, including eyes with keratoconus.
In cases of early keratoconus, a standard GP lens may be used. However, if the lens does not center properly on the eye or moves excessively with blinks and causes 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 stable on the eye, compared with traditional corneal gas permeable lenses.
Scleral Contact Lenses For Other Eye Problems
In addition to keratoconus, scleral contact lenses can be used for eyes that have undergone a cornea transplant, and for people with severe dry eyes caused by conditions such as Sjogren's syndrome, graft-versus-host disease (GVHD) and Stevens-Johnson syndrome.
Advances in lens design technology are allowing manufacturers to design scleral lenses that can correct more conditions than ever before, including bifocal sclerals for the correction of presbyopia.
Scleral Contact Lens Cost
Scleral contact lenses are custom-made 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 lens fitting, and several trial lenses of different sizes and curvatures may be applied to the eye during the fitting process.
Also, depending on the complexity of the problem and how the individual eye tolerates the scleral lens, adjustments of lens parameters may be needed, which will require additional lenses to be made and exchanged. The entire scleral lens fitting process can take several visits to determine the optimal lens for each eye.
While many individuals who use scleral lenses have worn soft or corneal GP lenses in the past, the process for applying and removing scleral lenses may take some practice. The additional time needed to master this, due to the larger size of the lenses and the fluid reservoir under the lenses, needs to be taken into consideration during the fitting process.
For these and other reasons, scleral contact lenses can cost significantly more than standard contacts; in fact, it is not uncommon for scleral contacts to cost three or four times more than standard lenses.