Viability test exclusively is not adequate to evaluate the T4 Acanthamoeba keratitis’ treatment

Acanthamoeba keratitis is a serious corneal infection and in some cases can lead to blindness.1 The T4 genotype is often associated with human infections by Acanthamoeba.2,3 The incidence of keratitis has increased considerably worldwide, especially those associated to contact lenses use.4,5 Cysts and recurrence of infection represent a challenge in the treatment of keratitis due to its high resistance to adverse conditions and to most medications.6,7 This intriguing property can lead to late diagnosis and can explain absence of cyst removal during and after therapy regimen.8 In early stage, due to symptomatology and incorrect diagnosis the disease can be inappropriately mistaken for keratitis by other microorganisms, such as fungi and bacteria, leading to treatment with antifungals or antibiotics that will not be effective. Therefore, delaying proper treatment for this infection can increase severity and risk of blindness.9