When the Bears were on the goal line Sunday in Atlanta, NBC color man Cris Collinsworth did a nice job of pointing out the Falcon safety and the options the Bears have depending on what the receiver and quarterback see.  The perspective of each will vary slightly due to the angle each have in looking at their reads, and them being on the same wavelength is critical to running an option route.  Many pass routes are called when the play is sent in, but many times the look of the defense determines what the receiver runs. 

The initial read by the wide out is how the cornerback is covering him; is he shading him one way or the other?  If he's really taking away the fade by lining up on the WR's outside shoulder, that might be an indication there is slant help to the inside, by means of a safety coming up or a linebacker or defensive end coming over.  If the DB is shading inside on the WR, thus giving him the fade (but taking away the slant), it's a good bet the DB thinks he will win the one on one against the WR.  He could be baiting the QB and WR into throwing the fade, just to give himself an opportunity to go up and make a play on the ball.  Your stronger and/or taller corners will try this, it's risky, but the best can get away with it.  Keep in mind that the few pure lock down corners there are in the league don't see much thrown their way down by the goal line anyway.

If the corner is playing straight up, the receiver then looks to the safety nearest him for his next read.  If the safety is cheating to the middle the WR then has to check the distance between a possible slant route and a potential LB or DE jumping the route.  If the WR has the room to keep his slant at a 45 degree angle, and himself between the DB and the ball, that's the ideal way to run the slant.  But on the goal line you have to try and split the difference between the safety and the next closest possible defender (LB or DE).  For example if the safety is really off or cheating middle the WR can take his slant deeper, but if the safety is up and the LB is clogging middle the WR then can flatten out his slant. 

One other option for the wide out is the back shoulder throw by the QB.  It's when the WR will start out like he's running a fade, but the QB will throw the ball behind the receiver allowing him to stop and pivot (and box out the DB), and make a play on the ball while the corner is in front of the receiver. Your bigger receivers (or tight ends split out wide) can have success with this.

One additional goal line option, and an option that is usually called in the huddle (however great chemistry between a QB and his receiver will allow this play to be run as an option read) is the slant/fade or the slant and go (terminology depends on the team).  The WR will run a slant, get a head and shoulder or pump fake from the QB then turn and dart to the corner as the QB lofts the ball where only his guy can get it.

All these wide receiver reads have to be done by the quarterback as well.  The difference is the perspective of the QB is different so a slight shade by the corner is harder to pick up.  Some teams use hand signals to get them on the same page, but with teams trying to maintain such secrecy they'd rather not signal to each other, instead relying on the numerous repetitions during practice to get them thinking the same way.

The QB will have more pre-snap reads to run through, as he has the other side of the field to concern himself with.  He'll have his primary receiver to check out, usually the receiver that has a single cover look.  After running through his options on one side, he'll then quickly scan the field to see what he can pick up with the other defenders.

On the 2nd quarter Greg Olsen TD, Jay Cutler didn't like the look he had on the left side after the ball was snapped.  Earl Bennett took a step inside then ran a fade, but was jammed up by the corner.  Olsen ran a skinny post with Desmond Clark coming underneath.  On the snap the Falcon safety went over to help with Bennett, leaving Olsen and Clark (who also could have received the TD pass).  Cutler hit Olsen, who ran by the defender, for a fairly easy TD.  But keep in mind all these pre-snap reads and post-snap reads take place in a matter of seconds, with an ever moving and changing defensive alignment, and this week in a loud hostile environment.