these are called overdone sapphire glows. ;)
Do you have any glow filters? Sapphire really does have a great glow effect. If you don't have a glow effect, you can stack a blur and a brightness together.
I like to flicker it a little before the transition, which is a bigger flash. These are just keyframes with size, threshold and brightness. Fun to play with.
often, I will use a quick 4 frame dissolve with the glow on the track above it as a transition. Depending on light sources on a shot, you can really come up with some cool stuff. As with CSI, it's a great way to play with jump cuts and chopped up dialog.
There's a very good glow-blur dissolve in the Nattress Film Effects package. Plus the rest of Graem's very excellent film inspired plugins. And there's a very nice glow in the Noise Industries FX Factory package. The 2 packages together are less than just the Lighting Box from Sapphire.
There's a neat little plugin available for Premiere/After Effects
from Buena called Effects Essentials. 'Camera Flash' is actually
part of suite costing $199, but 'Camera Flash' is the token
fully functional thing within it. And fortunately, when you look at
the rest of the suite, it's the only plugin you'll probably use.
Download it, install it, happily use 'Camera Flash' and not care
that you can't use anything else.