WHAT ARE SCLERAL LENSES?
Scleral lenses are made up of high oxygen permeable polymers. The name scleral refers to how the lens rests on the sclera or the white parts of the eye and the lens completely vaults over the cornea. The space between the cornea and lens is bathed in a preservative free solution, and provides a comfortable environment especially for patients with dry eyes. This lens is also a rigid contact lens, this feature allows it to bridge over any irregularity of the cornea, creating a perfect refractive surface for clear vision. These 2 features are what differentiate sclerals from soft contacts or rigid gas permeable (RGP) lenses.
The diameter of sclerals are also significantly larger than your average soft lenses, they range from 15mm to as large as 24mm. In comparison to soft contact lenses where the diameter caps at 14.5mm, and RGPs are no larger than 9.5mm. Although a 24mm lens can sound uncomfortable to wear, it is quite the contrary. Sclerals are designed to have very little movement on the eye, which translates to less lens awareness and more comfort.
WHO ARE SCLERAL LENSES FOR?
Due to sclerals’ ability to bridge over the entire cornea, patients with the following conditions can be treated with scleral lenses:
- Keratoconus
- Pellucid Marginal Degeneration
- Corneal Dystrophies: EBMD, Fuch’s Dystrophy
- High refractive errors: Extremely nearsighted or farsighted and severe astigmatism
- Post refractive surgery: LASIK, RK
- Post Corneal Transplant Surgery
- Dry Eyes Syndrome
- Stevens-Johnson Syndrome (SJS)
- And many more
FITTING PROCESS
A scleral lens fitting begins with a topographical scan of the cornea, this process is done with our Medmont Topographer, this allows us to capture a three-dimensional map of the surface curvature of the cornea. Any irregularities will be taken in consideration in order to design a lens specific to each eye.
The topographer then allows us to choose a diagnostic lens closest to the eye shape. The diagnostic lens will be applied in office to observe how the lens rotates, what type of modifications needs to be made for optimum comfort, as well as the prescription strength needed for a particular patient. To aid with getting the most precise measurements for these modifications, we use an instrument called an OCT (Optical coherence tomography). This technology allows us to make measurements of ocular structures, down to the microns.
These measurements are then sent to a lab which will manufacture the lenses to the exact specifications. The finished lens is expected to be an accurate fit. However, with more complex conditions, some adjustments will need to be made for optimum vision and comfort.
Contact our office for a scleral lens evaluation.