Acanthamoeba keratitis in adolescents with orthokeratology lenses

Background: With the rapidly increasing prevalence of myopia, progression-inhibiting techniques such as orthokeratology are increasingly being used; however, they harbor the risk of microbial keratitis, including Acanthamoeba infection, which is associated with delayed diagnosis, prolonged treatment and a potentially vision-threatening outcome.Material and method: This case series describes the diagnosis and course of treatment in four cases of Acanthamoeba keratitis in adolescents associated with the use of orthokeratology lenses, who were treated at the outpatient clinic for corneal diseases of the Department of Ophthalmology and Optometry at the Medical University of Vienna over a period of 1 year.Results: The four cases of orthokeratology-associated Acanthamoeba keratitis were diagnosed using corneal confocal microscopy and microbiological methods between August 2021 and August 2022. The intensive stepwise therapeutic approach included a high-dose, topical biguanide in combination with a diamidine derivative, which was combined with antibacterial and antifungal eye drops in the first phase of treatment. The course and success of the treatment was assessed using corneal confocal microscopy and adapted accordingly.Conclusion: Acanthamoeba keratitis is a serious infection associated with orthokeratology lenses. With respect to the age of the target group of this myopia progression-inhibiting treatment, besides careful patient selection, special attention should be paid to detailed training of contact lens wearers in the handling of the lenses as well as to an increased awareness of signs of early infection. As other methods for myopia control are available, patients need to be informed about the infection risk of orthokeratology.