Keratoconus is a condition where the cornea thins and bulges outward into a cone shape. Standard contact lenses are designed for spherical corneas — not conical ones. If you have keratoconus and are considering colored contacts for cosmetic purposes, here is what you need to know.
Standard Lenses Will Not Fit a Keratoconic Cornea
Yilala colored contacts use an 8.6mm base curve with a 14.5mm diameter. These measurements are designed for a normal corneal curvature. A keratoconic cornea has an irregular, steepened shape that a standard spherical lens cannot conform to. A standard lens will rock on the irregular surface, causing discomfort and potentially scratching the cornea at the cone’s peak.
Specialty Lenses Exist, but Options Are Limited
Scleral lenses — large-diameter rigid gas permeable lenses that vault over the entire cornea and rest on the white of the eye — are the standard treatment for keratoconus. Some scleral lens manufacturers offer tinted versions, but the color options are extremely limited compared to standard colored contacts. Talk to your cornea specialist about whether tinted scleral lenses are available for your specific prescription and corneal shape.
Do Not Attempt Standard Lenses on a Keratoconic Eye
The risk outweighs the cosmetic benefit by a wide margin. A poorly fitting lens on an irregular cornea can cause corneal abrasions at the cone’s apex, accelerate corneal thinning, and compromise the structural integrity of an already weakened cornea. If your eye doctor says no to contact lenses based on your corneal topography, accept that answer. No temporary change in eye color is worth permanent vision loss from a condition that is already threatening your eyesight.
For everyone else with healthy corneas: Browse FDA-registered colored contacts with standard 8.6mm base curve.