No one can doubt that reverse lights are an important aspect of any car. They are a necessary safety feature to prevent accidents, but you don't have to stick with stock backup lights if you don't want to. The Kia Optima is a very versatile car, in that there are tons of aftermarket add-ons you can install to upgrade the look. You could install aftermarket LED bulbs as your reverse lights for a crisp, xenon white glow as opposed to the dull color that you car rolled out of the factory with. If you follow the steps of this installation guide, you are well on your way to a nice set of LED reverse lights for everyone to see.
Open the trunk and find the handle located on the right side. Pry the handle cover off gently. There are two metal screws inside you need to remove.
Locate five (5) plastic screws that are closest to the hatch. Remove the two (2) bumper nubs as well in order to remove the trunk liner.
Pull the trunk liner down over the latch assembly to expose the wires.
This is the right tail light. The plastic wrapped wire must be disconnected before the remove the nut.
Remove two bolts at the side of the tail light assembly.
Push the side of the assembly upward to remove it from the trunk housing.
Twist and remove the stock bulb. Replace it with the new LED bulb.
Test to make sure it all works. Install everything back in reverse and repeat on the other side.
As you can see, the steps are very straightforward. Enjoy your LED backup reverse lights! Credit goes to red turbo from the Optima Forums.