This is a handy site
http://www.antiquespectacles.com/guide/guide_to_assist.htm
From there I learn these are known as oval lens scroll bridge - the site dates them 1870-1900. However I know from my own family that glasses like these were worn well into the 1930s 1940s. Glasses were not a fashion statement then - usually they were worn until they broke or were lost. I can't tell if they're child size - if the eyepieces are substantially less than 12 cms across, they may be. But actually glasses for children were not common back then, especially for the less well off. There was usually no such thing as eye testing, and if kids couldn't see they just moved closer to the front. Sometimes there are maker's marks on either the side pieces or under the bridge piece - the letters would be tiny. Also if they have any gold content, this would be on the bridge.
Usually the best way for an approximate date is from the case - they almost always had a printed trade name / address somewhere - if there is one you could Google and maybe find an advertisement for the dispenser.
