What conditions causes cracks in the field of vision and what meds would be prescribed to treat it?
Some people (me included) develop what you are calling cracks in their vision. This isn't too uncommon and they are called "floaters" and are nothing by undissolved dead capillaries that appear in your field of vision. There is really nothing medically that can be done for them. Sometimes they will go away with time, but some never do. They tend to become more common with age.
if it's sometimes like sparkles, lightning bolts or zig-zags, and is only temporary, like half hour or maybe up to a couple hours, then it may be ocular migraine. There does NOT have to be pain associated with ocular migraine. These are different than the painful migraine headaches. There are different types of ocular migraines. Some effect only one eye, some cause auras, or sparkles, or zig-zags. Some can be so strong that one is temporarily blind.
see: http://www.relieve-migraine-headache.com/eye-migraines.html
for one visual example of one type that sounds like yours, see: http://www.allaboutvision.com/conditions/ocular-migraine.htm
It first appeared after a bad dream involving me being passed out drunk on a burning couch.
I completely missed what i was going to say in my last post on this topic. It sounds closest to a zig-zag and it only lasted a few seconds and i had a short sharp headache after for a few minutes

It is probably not something that would respond to medication. I would see an opthomologist. Sometimes however, people will have vision disturbances from migrains or other problems with the brain like multiple sclerosis, which a neurologist would diagnose and treat.