Options for Keratoconus: Alternatives to RGP Lenses

For individuals with keratoconus, the traditional rigid gas-permeable (RGP) lenses can sometimes be uncomfortable. There are, however, a variety of alternatives available that can provide relief and improved vision. This article explores these options, including scleral lenses, hybrid lenses, and soft lenses, as well as soft contact lens piggy-backing.

Understanding RGP Lenses and Their Challenges

RGPs are designed to compensate for the irregularities of the cornea in keratoconus patients. However, not all RGP lenses are comfortable. This discomfort could be due to the irregularity of the cornea not being perfectly matched by the lens. Some patients find relief with scleral RGPs, which extend beyond the cornea to rest on the white part of the eye. Others may benefit from soft contact lenses worn underneath RGP lenses, which can cushion the hard lens and improve fit.

Scleral and Semi-Scleral Lenses

Scleral lenses are a more recent option that have gained popularity in managing keratoconus. These lenses are larger than traditional RGP lenses and fit over the irregular cornea, using the sclera (the white part of the eye) as a primary support. This design distributes pressure evenly, reducing discomfort and improving comfort.

Key Features:

Can accommodate a range of irregular cornea shapes Reduce corneal surface irregularities Provide excellent vision and reduced corneal abrasion

Hybrid Lenses

Hybrid lenses combine the benefits of both RGP and soft lenses. They feature a rigid center with a soft skirt, offering a balance of comfort and precise vision correction. Hybrid lenses can be particularly beneficial for patients who struggle with traditional RGP lenses.

Soft Contact Lenses

Soft lenses, while not as effective in managing keratoconus as rigid lenses, can still provide a comfortable alternative for some patients. Soft lenses can be worn alone or used in a piggy-back setup with an RGP lens on top. This combination can sometimes offer the best of both worlds, providing comfort and stability.

Revisiting and Refitting

For those with keratoconus, accurate fitting is crucial. It's always best to work with a corneal specialist who has the proper tools and experience. Regular re-fitting and adjustments may be necessary, especially as the condition progresses. A corneal topographer can help in determining the exact needs of the cornea, ensuring that lenses fit perfectly.

Considerations and K-Readings

Prior to fitting, it's important to let the RGP lenses rest off the eye for a few weeks to ensure accurate K-readings. These readings are essential for creating custom lenses that match the unique shape of the eye. A well-fitted and properly adjusted lens can significantly improve comfort and visual acuity.

Surgical Options

In severe cases, surgery may be necessary. This can include procedures such as collagen cross-linking, which can stabilize the cornea and prevent further thinning. Sometimes, a keratoprosthesis (cornea transplant with artificial materials) may be required. While surgery can offer a solution, it often leaves individuals needing to wear contact lenses or glasses afterward.

Conclusion

For keratoconus patients, the journey of finding the right contact lenses can be long and challenging. Fortunately, there are several alternatives to RGP lenses that can provide comfort and improved visual clarity. It's essential to work with a specialist who can tailor a treatment plan that best fits each individual's needs. Whether through scleral lenses, hybrid lenses, or other innovative solutions, there are options available to help manage this condition effectively.