To the Editor:
Corneal cross-linking (CXL) is the only treatment that potentially can block the progression of keratoconus, and studies showed low rates of failure or complication in patients older than 18 years.1 Nevertheless, there are only a few publications reporting about the outcomes and safety of CXL in patients younger than 18 years.2–4 We evaluated the complication rate of CXL for keratectasia in pediatric (younger than 18 years) and adult (18 years or older) patients for all eyes that underwent CXL from June 2008 through April 2014 in our clinical department.
CXL was performed under sterile conditions as an outpatient procedure using the standard Dresden protocol (ultraviolet-A light wavelength: 370 nm, irradiance: 3 mW/cm2).5 Postoperatively, a combination of betamethasone and neomycin eye drops was given four times daily with weekly tapering for 1 month, and a soft bandage contact lens was kept in place until full corneal reepithelialization occurred. Patients were advised to use preservative-free artificial tears for the first 6 postoperative months.
We assessed 133 eyes, including 103 eyes of adult patients and 30 eyes of pediatric patients. There were no significant differences between the patient groups regarding maximum keratometry value, thinnest corneal thickness, corrected distance visual acuity (CDVA), and follow-up time. A complication was defined as a loss of two or more Snellen lines of CDVA at the end of the follow-up compared to preoperatively. We observed complications in 2 eyes during the mean follow-up time of 13.5 ± 13.1 months, yielding a complication rate of 1.5% for all patients. Because both complications occurred in the pediatric patient group, the complication rate in this group was higher, with borderline statistical significance (P = .049). One 15-year-old patient presented with a severe bacterial keratitis 3 days postoperatively, and another 16-year-old patient showed an infectious crystalline keratopathy 3 weeks after the procedure (Figure 1).
(A) Infectious crystalline keratopathy in a 16-year-old patient 3 weeks after corneal cross-linking; when presenting, the patient was already wearing a rigid gas-permeable contact lens on the treated eye. (B) Central stromal scarring 18 months later in the same patient.
Our findings differ from previously recorded data,2–4 which may be related to different patient characteristics. Vinciguerra et al.4 reported no major complications after CXL in pediatric patients but, in contrast to our study, patients with poor compliance were excluded. The findings of Chatzis et al.,3 who found a similar safety profile for CXL in pediatric and adult patients, are also not directly comparable to our results due to an older mean patient age in their pediatric group (16.6 years) compared to ours (14.7 years). In the context of postoperative complications after CXL, a previous report about challenges due to lack of compliance in patients with Down syndrome is noteworthy.6
In our two cases with microbial infections, contact with the infectious agent likely occurred in the early postoperative period rather than during the surgical procedure, because CXL has a toxic effect on bacteria and fungi.7 Until complete healing of the epithelium, good compliance of the patient with regular application of antibiotic eye drops and avoidance of dust/dirt exposure is important. We want to highlight that parents and patients should be well informed about the recommended behavior after CXL. Furthermore, we strongly recommend close postoperative monitoring of pediatric patients with daily clinical controls of the treated eye in the first days after CXL to reduce the risk of severe complications.
Gernot Steinwender, MD
Laura Pertl, MD
Yosuf El-Shabrawi, MD
Navid Ardjomand, MD
- Koller T, Mrochen M, Seiler T. Complication and failure rates after corneal crosslinking. J Cataract Refract Surg. 2009;35:1358–1362. doi:10.1016/j.jcrs.2009.03.035 [CrossRef]
- Caporossi A, Mazzotta C, Baiocchi S, Caporossi T, Denaro R, et al. Riboflavin-UVA-induced corneal collagen cross-linking in pediatric patients. Cornea. 2012;31:227–231. doi:10.1097/ICO.0b013e31822159f6 [CrossRef]
- Chatzis N, Hafezi F. Progression of keratoconus and efficacy of pediatric corneal collagen cross-linking in children and adolescents. J Refract Surg. 2012;28:753–758. Erratum in: J Refract Surg. 2013;29:72. doi:10.3928/1081597X-20121011-01 [CrossRef]
- Vinciguerra P, Albe E, Frueh BE, Trazza S, Epstein D. Two-year corneal cross-linking results in patients younger than 18 years with documented progressive keratoconus. Am J Ophthalmol. 2012;154:520–526. doi:10.1016/j.ajo.2012.03.020 [CrossRef]
- Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003;135:620–627. doi:10.1016/S0002-9394(02)02220-1 [CrossRef]
- Koppen C, Leysen I, Tassignon MJ. Riboflavin/UVA cross-linking for keratoconus in down syndrome. J Refract Surg. 2010; 26:623–624. doi:10.3928/1081597X-20100824-01 [CrossRef]
- Iseli HP, Thiel MA, Hafezi F, Kampmeier J, Seiler T. Ultraviolet A/riboflavin corneal cross-linking for infectious keratitis associated with corneal melts. Cornea. 2008;27:590–594. doi:10.1097/ICO.0b013e318169d698 [CrossRef]