Suspected Caspofungin-Induced Visual Toxicity Manifesting as Temporary Decreased Vision: A Case Report

Introduction: Caspofungin is an echinocandin antifungal agent widely used for the treatment of invasive candidiasis because of its broad antifungal activity. Although ocular adverse events are listed among uncommon reactions in the Summary of Product Characteristics, detailed clinical descriptions of acute visual impairment temporally associated with caspofungin therapy are scarce. Case Presentation: We report the case of a 21-year-old man who developed candidemia due to Candida guilliermondii following complex spinal surgery. Antifungal therapy with caspofungin was initiated in accordance with current clinical guidelines. Within 24 hours of treatment initiation, the patient experienced a bilateral and symmetrical reduction in visual acuity, affecting both near and distance vision. Comprehensive ophthalmologic evaluation, including slit-lamp examination, fundoscopy, and optical coherence tomography, revealed no structural ocular abnormalities. Neurological assessment and neuroimaging were unremarkable. Visual symptoms persisted with fluctuating intensity during ongoing caspofungin administration and resolved completely within 48 hours after drug discontinuation, following a switch to micafungin. No recurrence of visual impairment was observed during follow-up. Causality assessment using the Naranjo algorithm indicated a probable association between caspofungin and the adverse event. Conclusions: This case describes a transient and fully reversible visual disturbance temporally associated with caspofungin therapy, in the absence of identifiable ocular or neurological pathology. While a causal relationship cannot be established based on a single observation, this report contributes descriptive safety data relevant to real-world clinical practice. Clinicians should consider careful evaluation of new-onset visual symptoms occurring during antifungal therapy and ensure appropriate pharmacovigilance reporting to support the identification of rare or unexpected adverse drug reactions.