Long-Term Outcomes Of Corneal Collagen Crosslinking In Pediatric Keratoconus: A Retrospective Multicenter Analysis

Keratoconus is a corneal ectatic disorder characterized by progressive corneal thinning and steepening, typically diagnosed in adolescence or early adulthood. In pediatric patients, keratoconus often presents with greater severity and rapid progression, making management particularly challenging. Corneal collagen crosslinking (CXL), which combines ultraviolet-A light and riboflavin to strengthen corneal fibers, has proven effective in halting disease progression. This study aims to evaluate the clinical and tomographic outcomes of pediatric patients who underwent CXL.

Ophthalmology Department of Unidade Local de Saúde de Coimbra (Coimbra, Portugal); Ophthalmology Department of Unidade Local de Saúde de São José (Lisbon, Portugal); Coimbra Ophthalmology Unit, Hospital da Luz de Coimbra (Coimbra, Portugal).

Multi-centric, retrospective, cross-sectional study including patients under 18 years old with progressive keratoconus who underwent corneal collagen crosslinking between 2010 and 2024. Different corneal collagen crosslinking modalities were performed, according to each patient’s characteristics and at the surgeon’s discretion. Best spectacle visual acuity (BCVA), manifest refraction, and tomographic parameters were evaluated and compared between baseline and follow-up visits. Progression was defined as KMax change superior to 1D.

Eighty-two eyes from 62 patients across three centers were included. Mean age was 15.09±2.24 years, with a mean follow-up of 40.70±30.89 months. Mean BCVA improved from 0.39±0.29 to 0.34±0.29 logMAR (p=0.30). Tomographic values remained stable, with no significant changes in K1 (49.11±4.57 to 49.53±5.15, p=0.30), K2 (54.17±6.17 to 54.42±6.55, p=0.52), and KMax (63.43±8.51 to 62.94±9.90, p=0.42). Fifty patients performed the Dresden protocol, 12 had accelerated CXL, 10 had simultaneous PRK, and 10 underwent a customized irradiation protocol. BCVA changes did not differ among protocols (p=0.60). KMax change differed significantly (p=0.04), with a greater flattening in simultaneous PRK or customized protocols. Eleven eyes (13.41%) progressed.

CXL halts keratoconus progression in pediatric patients while stabilizing visual acuity and tomographic parameters, regardless of the protocol used. Customized protocols and those including simultaneous PRK result in greater flattening, suggesting potential advantages in disease control. Our results reinforce the effectiveness of CXL as a first-line treatment for progressive keratoconus in children, helping to prevent or delay the need for corneal transplantation.