What Surgery Is Used to Treat Keratoconus?
Keratoconus is a progressive eye condition in which the normally round cornea thins and bulges outward into a cone shape. This distortion causes blurred vision, glare, and sensitivity to light. For many individuals, keratoconus can be managed with glasses or contact lenses in the early stages. However, as the disease progresses and the cornea becomes increasingly irregular, surgical intervention may become necessary to restore vision and prevent further deterioration.
When Is Surgery Needed for Keratoconus?
Surgery is typically considered when vision cannot be adequately corrected with glasses or contact lenses, or if the cornea is thinning rapidly. Advanced keratoconus can cause scarring or extreme irregularity that severely impairs vision. In some cases, patients experience contact lens intolerance due to discomfort or poor fit.
The goal of surgery is to stabilize the cornea, improve its shape, and restore functional vision. The choice of surgery depends on the severity of the condition, patient age, and the specific characteristics of each cornea.
Corneal Cross-Linking
Corneal cross-linking is a minimally invasive procedure used to halt the progression of keratoconus, especially in its early to moderate stages. This treatment strengthens the cornea by increasing the collagen bonds within it.
The procedure begins by applying riboflavin (vitamin B2) drops to the cornea. The eye is then exposed to ultraviolet A light. This combination activates a biochemical reaction that stiffens the corneal tissue, making it more resistant to bulging.
Cross-linking does not reverse existing corneal distortion but can prevent further progression, allowing patients to preserve their current level of vision and delay or avoid more invasive surgery.
Intacs and Intracorneal Ring Segments
In some cases, small arc-shaped segments called Intacs or intracorneal ring segments are surgically implanted into the cornea. These rings help reshape the cornea by flattening the cone and improving its symmetry.
This procedure can improve vision and reduce dependence on thick or specialty contact lenses. It is generally recommended for patients with moderate keratoconus who still have relatively clear central corneas.
The surgery is relatively quick and typically performed under local anesthesia. While Intacs do not stop disease progression, they may delay the need for corneal transplantation.
Corneal Transplantation
Corneal transplantation is often required for advanced keratoconus when other treatments are insufficient. It involves replacing the damaged cornea with a healthy donor cornea.
There are two main types of corneal transplant for keratoconus. Penetrating keratoplasty involves replacing the full thickness of the cornea and has been the traditional approach. More recently, deep anterior lamellar keratoplasty (DALK) has gained popularity. DALK replaces only the front layers of the cornea and preserves the patient’s inner corneal tissue. This technique reduces the risk of rejection and other complications while providing excellent visual outcomes.
Transplant surgery requires general or local anesthesia and several months of postoperative care including medications and monitoring. Patients may need corrective lenses after surgery, but many achieve significantly improved vision.
Combined Procedures and Emerging Treatments
In some situations, corneal cross-linking is combined with other treatments like Intacs or laser procedures to enhance success. These combined approaches aim to provide better visual improvement while stabilizing the cornea.
Research continues on new technologies such as customized laser treatments, stem cell therapy, and advanced implant materials to offer safer and more effective options for keratoconus management in the future.
Risks and Considerations
All surgical procedures carry risks and limitations. Cross-linking can cause temporary pain, light sensitivity, and delayed healing. Intacs may lead to infection, extrusion, or irregular astigmatism. Corneal transplantation risks include rejection, infection, and astigmatism requiring additional treatment.
Choosing surgery involves careful consideration with the eye care provider to weigh the benefits, risks, and expectations.
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