Christopher Kim's 2012 article is definitely worth a read.

http://brown.edu/Departments/Joukowsky_Institute/undergrad/prizes/Kim2012.pdf - nice charts and maps and illustrations

And someone's evidently been working on the Wikipedia info:

Eye Beads
The earliest types of glass objects found in China are polychrome eye beads or dragonfly-eyed beads. The beads are found in burials from the late Spring and Autumn and early Warring States periods (early 5th century BC) up to late Warring State – early Western Han period. Most beads have a monochrome glass body covered by several layers of coloured glass. The layers of different colour glass are applied in alternating fashion to produce concentric circles.The patterns of circles resemble eyes, giving the beads their name. This style of bead originated in the Near East during the mid 2nd millennium BC. The stylistic influence later spread to the Mediterranean, Central Asia and China.

During the early 5th century BC, the imported eye beads were considered exotic objects. They were mainly deposited in high status burials, such as the tomb of a male aristocrat of the Qi state at Langjiazhuang, Shadong. This situation changes during the middle and late Warring States Period. Eye beads from this period are manufactured from Chinese lead-barium glass and are mainly found in the regions of the middle Yangzi River Valley, indicating a connection to the Chu kingdom. In this context, the beads became more common and available to a larger part of the Chinese society. Evidence of this is the presence of eye beads in medium and small burials, with modest funerary furnishings, as well as large, high-status burials.

The use of eye beads in burials rapidly declined at the beginning of the Western Han period. This is believed to be a result of the invasion of Chu kingdom territories by Qin and Han armies at the end of the 3rd century. The collapse of the Chu kingdom would have brought production of eye-beads to an end.