Suspected cumulative neuro-ophthalmic toxicity after chronic oral exposure to the veterinary anesthetic tiletamine: a case report

Abstract

Background Tiletamine, commonly formulated with zolazepam as Zoletil ® /Telazol ® , is widely used in veterinary anesthesia; however, human data regarding potential cumulative neuro-ophthalmic toxicity after long-term exposure remain limited. Case presentation A 24-year-old man developed progressive bilateral visual decline (left worse than right) after >1 year of non-medical oral exposure to a suspected tiletamine-containing product obtained online. He also reported persistent dyschromatopsia, dysarthria, and gait instability after cessation. Best-corrected visual acuity was 20/25 (right) and 20/50 (left). Fundus and ultra-widefield imaging were unremarkable. Optical coherence tomography showed bilateral fovea-centered outer retinal/photoreceptor-layer disruption with scattered hyperreflective foci. Full-field electroretinography was within normal limits, whereas visual evoked potentials revealed reduced P100 amplitude in the left eye with preserved latency. Brain MRI demonstrated mild diffuse cerebral and cerebellar sulcal widening compatible with early atrophy. Alternative causes, including inherited retinal degeneration and other established retinotoxic exposures, were not supported by the available evaluation. Short-term follow-up showed clinical stability with limited recovery. Conclusion This case suggests a possible temporal association between prolonged oral exposure to a suspected tiletamine-containing product and combined retinal and neurological abnormalities. Because toxicological confirmation and independent formulation verification were unavailable, causality cannot be established. The findings highlight the need for One Health–oriented toxicovigilance and longitudinal neuro-ophthalmic monitoring when similar exposure is suspected.