Abstract
Purpose:
To analyze progression after corneal cross-linking (CXL) in children with keratoconus.
Methods:
Retrospective evaluation of tomographies (Pentacam) and topographies (TMS) of prospectively collected data after CXL in children younger than 18 years. Examinations were conducted prior to surgery at regular intervals during the first postoperative year, and at 2, 3, and 4 years after the procedure. Twenty-five patients (33 eyes) were included in the study. Mean follow-up was 27.3 months, and the minimum follow-up 1 year. Mean age at the time of surgery was 14.9 years. Progression was defined as an increase in Kmax (Pentacam) of at least one diopter (D) in 1 year.
Results:
669 KMax comparisons were made, resulting in the identification of 4 cases of progression. In one case, the keratoconus was extremely advanced prior to CXL (Kmax 78.2D before surgery and 79.3D at 1 year). One case showed marked steepening of 3.4D in the Pentacam between 3 and 4 years after CXL, but the TMS parameters were unchanged. Because of this discrepancy, the Pentacam exam was repeated and showed that Kmax was actually stable, i.e. no progression after all (50.8D at 3 years and 50.7D at 4 years). Two children with active limbal vernal keratoconjunctivitis worsened dramatically (46.4D at 1 year and 48.3D at 2 years; 53.6D at 1 year and 54.9D at 2 years). This progression was also seen in topography. After resolution of the limbal inflammation, the Kmax values returned to 46.3D and 54.2D, respectively.
Conclusions:
Our results confirms that CXL is very effective in stabilizing keratoconus in children. True progression after CXL could only be verified in 1 out of 33 eyes, but that eye had already progressed to such an extreme extent prior to CXL, that it was probaby unrealistic to expect that CXL could arrest progression at such a late stage. Further, in assessing possible progression, the use of 2 different measuring devices can help detect discrepancies and thus prevent false conclusions. Moreover, limbal vernal changes can present a clinical picture of progression. However, this is actually a pseudo-progression, that can be reversed with anti-inflammatory treatment.
Keywords: 574 keratoconus •
479 cornea: clinical science