Scleral contact lenses are large, rigid gas permeable lenses designed to rest on the white of the eye and vault over the entire corneal surface. They are frequently used when the cornea has an irregular shape due to conditions like keratoconus, pellucid marginal degeneration, or a previous corneal transplant. For patients in Las Vegas seeking clearer vision with an irregular cornea, customizable scleral lenses offer a precision-fit solution.
Because scleral lenses often serve patients with complex corneal shapes, they are designed to be highly customizable. The key parameters that can be adjusted include center clearance, limbal clearance, and edge lift. Scleral lenses can also be manufactured with nearly any prescription, including corrections for nearsightedness, farsightedness, and astigmatism.
An irregular cornea is any cornea with an abnormal shape or surface pattern on its front or back surface. Often, this presents as an area of the cornea that protrudes outward more than the surrounding tissue, creating uneven light refraction that glasses and soft contact lenses cannot fully correct.
Keratoconus is one of the most common causes. In keratoconus, the cornea progressively thins and steepens, typically in the lower portion, forming a cone-like shape rather than a smooth, even curve.
Another common cause is a cornea that has undergone a corneal transplant. While transplant surgery can restore corneal clarity, the healing process often results in irregularities, including areas of elevation or depression where the donor tissue meets the host cornea. These irregularities can make standard vision correction inadequate.
Scleral lenses work very differently from traditional soft contact lenses. Soft lenses drape over the cornea and conform to its shape, which means they take on the same irregularities that are causing vision problems.
Scleral lenses, by contrast, are large and rigid enough to maintain their own smooth optical surface. When placed on the eye, the lens vaults over the cornea entirely, and the space between the lens and the cornea fills with preservative-free saline. This creates a new, perfectly smooth refracting surface that replaces the distorted corneal surface for vision purposes.
As a result, scleral lenses can provide significantly sharper vision than glasses or soft contact lenses for patients with irregular corneas, often eliminating the ghosting, doubling, and distortion that these patients experience.
Fitting a scleral contact lens begins with placing a diagnostic trial lens on the eye in the office. The trial lens is selected based on detailed measurements of the cornea and sclera, often using advanced imaging such as corneal topography or sMap 3D corneo-scleral mapping.
Your eye doctor evaluates how the trial lens fits across different zones of the cornea. If the center clearance, limbal clearance, or edge lift needs adjustment, those parameters are modified on the custom lens that is ordered for you. This process ensures that your final lens is tailored to your specific eye anatomy.
Center clearance refers to the amount of space between the back surface of the scleral lens and the center of the cornea. This is arguably the most important fitting parameter because it determines how well the lens vaults over the cornea.
The lens must clear the cornea with enough room to maintain a healthy fluid reservoir, but not so much that it causes excessive lens movement or blurred vision. Your doctor fine-tunes this measurement to balance comfort, corneal health, and visual clarity.
Limbal clearance refers to the space between the lens and the cornea at the limbus, the junction where the cornea meets the sclera near the edge of the iris. Proper limbal clearance is essential for maintaining healthy tear exchange beneath the lens.
If limbal clearance is too tight, it can restrict fluid flow and compress delicate limbal tissue. If it is too loose, the lens may not seal properly. Adjusting this parameter improves both comfort and the long-term health of the ocular surface.
Edge lift describes the angle at which the outer edge of the scleral lens meets the scleral surface. This parameter directly affects how the lens feels on the eye throughout the day.
If the edge is too steep, it can create pressure points that cause discomfort or leave marks on the conjunctiva. If it is too flat, the lens may not maintain a proper seal, allowing air bubbles to enter beneath the lens. Your doctor adjusts edge lift to achieve a comfortable, stable fit that you can wear throughout the day.
At Insight Vision Optometry, Las Vegas, Dr. Stephanie Woo, OD, FAAO, FSLS, Dr. Nathan Schramm, OD, FSLS, FBCLA, and Dr. Thanh Mai, OD, FSLS are experts in designing and fitting customizable scleral contact lenses for keratoconus, corneal transplants, and other complex corneal conditions. Call 702-747-4070 or visit www.insightvisionlv.com to schedule your scleral lens consultation.
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