In 1884, cocaine was first used as a local anaesthetic to immobilize a patient's eye for eye surgery by Carl Koller. His success initiated the modern era of local anesthesia, with cocaine also quickly adopted for nose and throat surgery and for dentistry. For Koller, a Czech-born American ophthalmologist, the clue for this use was when he noticed that cocaine had a numbing effect on the tongue. He made many experiments on animals before introducing its use on humans. Cocaine was isolated in 1859 and was synthesized in 1885. It was later found with high doses or repeated use, it caused erosion of the corneal epithelium in high doses and it was replaced by less toxic, synthetic local anesthetics such as tetracaine and proparacaine.«