Corneal inflammatory events during orthokeratology: analysis of 600 cases over two decades

To investigate the occurrence of corneal inflammatory events during orthokeratology (ortho-k) treatment in patients over a 20-year period, and to identify risk factors related to the most common type of inflammatory complication.

Retrospective analysis was conducted on 600 patients (mean age: 13.2 years; range: 7-50 years) who were fitted with ortho-K lenses between 2005 and 2024. All cases of keratitis, including both infectious and non-infectious (inflammatory) forms, were recorded. The mean follow-up time was 4.2 years (range: 0.5-19 years). Logistic regression analysis was performed to investigate associations between keratitis occurrence and potential risk factors, including age, sex, spherical equivalent (SE), corneal thickness, meibomian gland dysfunction (MGD), history of ocular allergy, and participation in water sports.

Among 600 patients (1193 eyes), no cases of microbial keratitis were observed, while infiltrative keratitis (IK) occurred in 20.2 % of patients predominantly within the first two years of lens wear. Participation in water sports (p < 0.001), presence of meibomian gland dysfunction (p < 0.001), and higher baseline spherical equivalent (p = 0.002) were significantly associated with increased risk of IK. No significant association was found between IK and age, sex, baseline pachymetry, or history of allergy.

Infiltrative keratitis was a relatively common inflammatory complication during ortho-K wear. Water sports participation, MGD, and higher myopic refractive error were significant risk factors for IK. Regular follow-up, especially during the first two years, careful management of ocular surface health, and consideration of preservative-free cleaning systems are recommended to reduce IK incidence in ortho-K patients.