Not sure exactly what optic you are referring to, but going off the assumption it is a standard reflex type red dot sight.
If you are using a red dot sight correctly, you won't notice the front sight at all.
Just like if you put your right had up in front of your right eye while leaving your left eye open, you "see through" your hand.
It works the same for red dot sights. You shouldn't close one eye and look through it like you do a traditional magnified optic.
Keep both eyes open and look at the target, then place dot on the target while keeping focus on the target.
The only thing that might be a problem is if you have bad uncorrected astigmatism. It can make the dot flare so bad that it becomes difficult to use.
It will help to use a lower 1/3 cowitness.
http://www.google.com/search?q=lower...w=1207&bih=723
I personally like Primary Arms and they can also help you with what you should buy and what works with different setups. They are a great bunch of guys, I try to buy stuff from them 1st because they are so good to deal with.
https://www.primaryarms.com/