Re: spiked appearance of bright light source

    Sorry for the delay, I had trouble retrieving my email for the last 
week...
    
    OK, so someone previously tried to answer your question but apparently 
did not answer it to your specifications.  I will try my best to answer 
your question as best I see it.

    It seems that what you are asking is why you are "seeing" this spiking 
effect from light sources such as street lamps.  I would interpret this in 
a few ways.  For one, the covering on a street lamp has inperfections in 
the bulb surface or outer transparent covering, meaning that it is not 
perfectly smooth.  Because of this the rays emanating from the source 
refract and reflect in ways that divert the rays.  When this happens you 
will see a spiked appearance to the light source or that interferance is 
occurring with the rays overlapping.  This results in destructive and 
constructive interference which we see as bright and dark spots coming off 
a light source such as this.  
    Things like the moisture in the air, windshields, and even the air 
cause these rays to deviate in the space between you and the light 
source.  Some people also see spiked appearances to light sources if there 
eyes don't focus properly, such as in far-sighted and near-sighted people.

I hope that I answered your question or at least gave you some things to 
investigate.  If you have further questions are want elaboration on any of 
these items let us know.  Thanks