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. Scleral contacts are noticeably larger than standard Gas Permeable (GP) contact lenses and have a diameter equal to or greater than that of soft contact lenses. The smallest scleral lenses are 13.5 mm in diameter, and the largest can be up to 20 mm. The average human cornea is approximately 11.8 millimetres in diameter, so even the smallest Scleral contacts are designed to cover the entire corneal surface.
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. Due to their size, Scleral lenses do not dislodge with quick eye movements, airborne particles and dust rarely get under the lens and lastly, we’ve yet to see a case of lenses dislodging. All these factors make Scleral lenses a good option for patients who play sports or lead active lifestyles.
They 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. In cases of early keratoconus, a standard GP lens may be used. However, if the lens does not centre properly on the cornea or moves excessively with blinks and causes discomfort, switching to a large-diameter scleral contact lens may solve the problem.
In addition to Keratoconus, ideal candidates for Scleral lenses include any patient with an irregular corneal surface. This includes patients with pellucid marginal degeneration, post-penetrating keratoplasty (post-PKP), corneal scarring, irregularities following refractive surgery and ocular surface disorders. Our experience has shown that patients with these conditions are most appreciative of the benefits that accompany Scleral lenses. For some patients, fitting Scleral lenses may eliminate or delay the need for corneal transplant surgery.
Scleral contact lenses are custom-made for each wearer, so fitting Scleral contacts demands greater expertise and more time than fitting standard soft or RGP contact lenses. We use 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. During your contact lens exam and fitting, we will determine the best Scleral lens type and size for your specific needs.
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.
Therefore, 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.
Most insurance programs do not automatically cover the full cost of Scleral contact lenses. In other instances, contacting your medical insurance provider and inquiring what steps are necessary to obtain coverage can be helpful. Ask the doctor’s rooms for details.