MintViz posts a look at using V-Ray’s Lens Effects Plugin to create lighting effects such as light bleeding Glare and Lens Bloom effects.
This tutorial shows you how to setup the V-Ray Lens Effects pluginMintViz
The post notes that the lighting effect can happen in real life when you are taking a photograph of a light source that is much brighter than the surrounding environment.
The effect can appear in areas that are extremely bright and that can usually lead to the tell-tale black edges that are largely caused by over exposed pixels. It is the exchange between extremely bright pixels to darker ones that makes this anomaly happen.
MintViz shows how to recreate this effect using the V-Ray Lens Effects. The tutorial also has a look at creating your own glare filter using the Filter Generator.