Keratoconus is a condition that affects the shape of the transparent dome of the eye called the cornea.
The cornea acts as a window, allowing light to pass into the eye. Keratoconus makes the cornea protrude outward and bulge in the shape of a cone. The thinner, misshapen cornea distorts light rays and creates refractive problems like blurred vision, sensitivity to light and glare (National Keratoconus Foundation).
If you have keratoconus, you can still wear contact lenses. However, you will likely need your ophthalmologist to prescribe custom lenses to accommodate your corneal shape. It’s not always necessary to wear hard contact lenses, but your choices may be limited to specialized types of soft or gas permeable contact lenses that can compensate for the irregular shape of the cornea.
Your ophthalmologist may recommend one of these types of lenses:
- Rigid gas permeable lenses (RGP or GP): These are the most frequently prescribed type of lens for patients with keratoconus. RGP lenses allow oxygen to permeate through the lens into the cornea to provide optimum breathability. Your ophthalmologist can customize RGP lenses to fit your corneal shape. Most patients find that RGP lenses require minimal care and are simple to insert and remove. Unfortunately, they are not a long-term solution for many people with keratoconus.
- Hybrid lenses: This type of custom contact lens is soft around the outer edge but gas-permeable in the middle. The rigid center provides structure for the cornea and optimal visual correction, while the flexible exterior offers comfort. This type of lens is becoming much more popular than traditional RGP lenses due to increased comfort.
- Piggyback lenses or tandem lenses: This dual-lens system involves placing a soft contact lens on the cornea and a corneal gas permeable lens or hybrid lens on top of the soft lens. Many patients find that the soft contact lens creates a buffer between the harder surface of the gas permeable lens and the cornea.
- Scleral lenses: A scleral lens is a gas permeable lens that has a larger diameter than most contact lenses. It is designed to curve over the cornea and center on the white part of the eye called the sclera. This lens requires you to fill the bowl of the lens with saline before applying it to the eye.
If you have keratoconus, it may limit some of your contact lens options, but your ophthalmologist can help you select a lens that offers comfort and visual clarity. It’s important to choose a qualified professional to treat your keratoconus. You will need to visit your ophthalmologist more frequently for comprehensive eye exams and contact lens check-ups. Your eye doctor will monitor your corneal shape and make changes to the power and shape of your contact lenses as needed. If your cornea is unstable and the shape is becoming more and more like a cone, than surgical intervention with corneal cross-linking may be necessary.
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