AIM:To assess the affect of ketamine and xylazine (ketamine/xylazine) to the transient lens opacity in mice.METHODS:Kimba mice (n=10) and wild-type mice (wt,n=8) were sedated with intraperitoneal injection of ketamine (60mg/kg for mice) and xylazine (10mg/kg) at 4,8,12 and 16 weeks old respectively. Pupils were dilated with tropicamide 25g/L alone to allow imaging lens status and retina using Spectralis HRA+OCT. RESULTS:All Kimba mice and wt presented extreme proptosis,suppression of the eye-blink reflex,corneal surface drying and lens opacities which occurred as early as 21±6 minutes after giving anesthesia and the lens opacities lasted up to 150±24 minutes.CONCLUSION:Ketamine/xylazine can cause transient lens opacity that may be related with the drugs’ side-effect.