Hi.. Thanks for the query.. If you have a severe sinus infection then blurred vision can be due to sinus infection only.. This is because there are large sinuses present behind the ears and infection and inflammation of the sinuses can cause pressure over the eyes causing blurry vision.. So it is advisable to consult an Emergency room and get evaluated and a PNS view x ray of sinuses and an MRI scan can be done for confirmation. You can be advised stronger antibiotics like Augmentin [Amoxicillin - Clavulanate potassium], anti inflammatory painkillers like Ibuprofen. Use decongestant nasal sprays like Oxymetazoline to reduce pressure and congestion.. Do steam inhalation and saline nasal irrigation.. You should avoid exposure to very cold air and cover the nose and mouth.. Avoid air conditions atmosphere. Hope this helps.. Regards.