A blocked tear duct is most common in new-born babies, but still existing in older children and adults. And the time it lasts just depends, ranging from weeks to months. But usually it will be no more than one year. When one get a blocked tear duct, the most important thing to do is massage the area, both outside and the inside of the corner of eyes, which can be really effective for helping clear the duct. Also, you can do some cleaning with cooled sterile water and you can use a cotton wipe regularly to stop some infections occurring around your eyes. Just take care and it is not very bad!
I must admit that suffer blocked tear duct is not a good thing. Blocked tear duct most commonly occurs on new born babies. But it does not mean that adult's can avoid it. On the contrary, if adults who get blocked tear duct, it really troublesome because adults need to receive medicine treatment, sometimes even surgery. However, for the majority of new born babies, blocked tear duct will clean by itself in 6 months. Some may automatically heal in 10 months. When it comes to how long blocked tear duct lasts on adults, oculists will say no exactly time. In adults, blocked must be treated, that is, you need take notes from an oculist, take medicines and drop some special drops everyday. And you have to clean eyelids carefully every morning and night. To sum up, you'll be fine in 2 weeks if you receive professional medicine treatments. Good luck for you.