BLOG: CXL most effective choice for pediatric keratoconus
Pediatric keratoconus is often an undiagnosed condition that results in many cases being untreated.
As this patient population has a vulnerable developing visual system, a delay in treatment can lead to lifelong visual consequences.
With the fast rate of progression found in childhood keratoconus compared with adult-onset keratoconus, initiation of treatment is imperative. Management options have shifted over the past decade with the success of corneal collagen cross-linking (CXL) and, as a result, it is important to understand the role each available treatment option has for our children with keratoconus.
Contact lenses are a nonsurgical option for pediatric keratoconus, with standard gas-permeable (GP) lenses and scleral lenses providing great visual success in children. Although GP contact lenses can provide visual assistance for our pediatric patients they are not viewed as a long-term treatment option by themselves.
This conservative modality does not halt the progression of the disease but can provide a long-term visual benefit when used in conjunction with CXL.
The data in the pediatric population are limited, but the available cases show intracorneal ring segment (ICRS) implantations to be tolerated well with an adequate visual outcome initially (Olivo-Payne et al.). Although this seems like promising information, ICRS implantation is not a commonly used treatment in pediatric patients due to the aggressive progressive nature of pediatric keratoconus, frequent associated eye rubbing and unpredictable results (Venugopal et al.). These findings lead to ICRS being a short-term solution and not a viable long-term treatment modality.
Studies evaluating the combination of ICRS implantation with CXL show stable topographic findings and good visual outcomes. With more than 20% of keratoconus patients intolerant to contact lenses (Olivo-Payne et al.), this dual treatment modality may be an option to consider in the future for a specific group of patients. As the data are minimal, more studies are needed to understand the long-term success in children.
Overall, ICRS alone does not halt the progression of keratoconus and should not be viewed as standard of care for pediatric keratoconus.
CXL is a technique that uses ultraviolent A (UV-A) light and riboflavin to increase the biomechanical rigidity of the cornea and arrest progression of ectasia in patients with keratoconus. The original protocol removes the epithelium (epi-off) prior to application of riboflavin and UV-A light. Long-term topographic stabilization has been well-documented in the pediatric patient population, as well as noted visual improvement (Caporossi et al.). Currently the Glaukos iLink procedure is the only FDA-approved CXL system in the U.S.
An alternate CXL method explored refraining from epithelium removal (epi-on) prior to application of riboflavin and UV-A light. This method was investigated to potentially reduce postoperative pain and infection. Unfortunately, the current epi-on CXL technique does not allow adequate penetration of riboflavin, leading to decreased absorption of UV-A in the stroma As a result, it does not provide long-term stability for pediatric keratoconus (Venugopal et al.).
Researchers are investigating adjustments to the riboflavin, UV irradiation and oxygen consumption, which may lead to the modified epi-on procedure being a viable option for our pediatric patients in the future.
Corneal transplants for keratoconus in the pediatric population represent 15% to 20% of all corneal transplants (Olivo-Payne et al.). These procedures come with a multitude of perioperative, intraoperative and postoperative risks. In addition, younger age at time of transplantation has been associated with a higher risk for rejection, leading to increased need for multiple transplants and a poor visual prognosis (Venugopal et al.).
Although this is a possibility, and sometimes the only option, for an advanced stage of keratoconus, it certainly presents with high risks and does not guarantee a successful visual outcome.
In summary, after the diagnosis of keratoconus has been made it becomes paramount to stop the progression of this condition to prevent deterioration in the longstanding visual outcome of these children. Although the options for managing these children can be overwhelming, CXL is the only treatment for pediatric keratoconus that has been proven to halt progression of the disease and prevent prolonged reduction in a child’s visual acuity.
- Caporossi A, et al.. J Ophthalmol. 2011;2011:608041. doi.org/10.1155/2011/60804.
- Olivo-Payne A, et al. Clin Ophthalmol. 2019;13:1183-1191.
- Venugopal A, et al. Indian J Ophthalmol. 2021 Feb;69(2):214-225.