WIO 2023: Cross-linking in pediatric patients: The case for treating keratoconus without waiting for disease progression

(Image Credit: AdobeStock/Pavel Losevsky)

Maria A. Henriquez, MD, MSc, PhD, talked about the paradigm shift regarding treating keratoconus in children. Ten years ago, a debate existed about whether or not to treat them with corneal crosslinking (CXL). In 2023, corneal CXL should be indicated in a patient with progressive keratoconus. Now, the debate is whether to wait for progression or not to perform the procedure.

Henriquez, Chair of the Research Department at Oftalmosalud, Instituto de Ojos, Lima, Perú, discussed this topic at the 2023 Women in Ophthalmology Summer Symposium in Marco Island, FL.

She cited her recent article in which she argued why clinicians should not wait for keratoconus to progress before treating high-risk pediatric patients because of the inherent risks involved in waiting.¹

Her argument is in contrast to another recent article in which the author advocated for waiting for keratoconus to progress before performing CXL.² The author’s key point was that there is no urgency in treating pediatric patients with KC without proof of progression and recommended treating the chronic ocular allergy and inflammation to stop the progression of KC.

Henriquez pointed out that waiting for keratoconic progression runs the inherent risk that keratoconus will progress rapidly and affect the planned initial treatment protocol. She provided an example of a patient who had an increase of 2.50 diopters in the maximum keratometry and a decrease in the thinnest pachymetry of 54 microns with 4 months of waiting.

The Case for Immediate Treatment

The loss of follow-up of a pediatric patient with keratoconus may result in the patient becoming a candidate for a penetrating keratoplasty (PK).

Research over the past decade has identified these noteworthy findings, ie, ectasias are the major indications for pediatric PK in the US, the time period for PK is significantly shorter in younger patients (<18 years), and corneal thinning or scarring or hydrops develops in 86% of children in a period from 5 to 30 months.

In contrast, 5 to 10 years after CXL only 3% of the eyes required a PK, she emphasized.³

“Conservative management instead of CXL is not advisable,” she said, “because the side effects of chronic treatment such as immunomodulatory therapy and also because of the increased risk of corneal scarring in chronic contact lens wearers.⁴

Eye rubbing in keratoconus

According to a previous study published by her group, Dr. Henriquez explained that keratoconic corneas react biomechanically differently to eye rubbing compared to normal eyes.⁵ Therefore, eye rubbing control should be an adjunct treatment and not an alternative treatment to CXL, since cases of progression associated with eye rubbing can occur “before and after” CXL.

Picking the procedure

Once the decision about surgery has been reached, the next decision involves the choice of procedures: transepithelial CXL or epi-off CXL.

Both have associated pro and cons.

The epi-off procedure has a higher complication rate (4%) and increased postoperative discomfort; the pros are greater efficacy and lower disease progression.

In contrast, transepithelial CXL is characterized by lower efficacy and increased but acceptable disease progression; however, the procedure has a lower complication rate (2%), decreased postoperative discomfort, and equivalent visual and refractive outcomes, according to Henriquez.

The criteria to decide which treatment to choose are based on risk factors for progression and complications and keratoconic severity.

Important practical considerations for surgeons include the fact that epi-off CXL is more aggressive in flattening the keratometric (K) readings than epi-on; this is important when thinking about the desirable effect on the cornea, its effect on visual acuity and risk of progression in each patient,ie, patients with high K readings would benefit from higher flattening effects and patients with mild KC in whom stable K readings or less flattening is desired.

The take-home messages were as follows:

• The risk factors associated with progression and loss of follow-up must be considered to decide the treatment urgency. High risk patients require prompt CXL, and low-risk patients require control of eye rubbing and inflammation and close follow-up.
• The efficacy of transepithelial CXL is inferior to the epi-off protocol although the former is significantly safer.
• The type of treatment should be decided based on the severity of the KC, the risk of progression and complications, and the predictive keratometric flattening and its effect on the visual acuity.

References:

1. Henriquez MA. Argument for prompt corneal cross-Linking on diagnosis of keratoconus in a pediatric patient. Cornea. 2022;41:1471-2.

2. Abad J-C. Childhood cornealcross-linking: Follow-up to document progression to intervene. Cornea. 2022;41:1473.

3. Henriquez MA, Hernandez-Sahagun G, Camargo J, Izquierdo L Jr. Accelerated epi-on versus standard epi-off corneal collagen cross-linking for progressive keratoconus in pediatric patients: five years of follow-up. Cornea. 2020; 39(12):1493-8.

4. Wagner H, Barr JT, Zadnik K. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: methods and findings to date. Cont Lens Anterior Eye. 2007;30:223-32.

5. Henriquez MA, Cerrate M, Hadid MG, Cañola-Ramirez LA, Hafezi F, Izquierdo L Jr. Comparison of eye-rubbing effect in keratoconic eyes and healthy eyes using Scheimpflug analysis and a dynamic bidirectional applanation device. J Cataract Refract Surg 2019;45(8):1156-62.

Maria A. Henriquez, MD, MSc, PhD

Henriquez is Chair of the Research Department at Oftalmosalud, Instituto de Ojos, Lima, Peru. She has no financial interest in this