After opening door, start to close door and stop it right away, this will stop the lights from coming on whenever you enter or leave the garage.

From the owners manual:

With the light off, press and hold the light button for 10 seconds, until the light comes on, then off again.

If you don't have the manual, you can download a copy from the Chamberlain web site.

To have your lights come on automatically when you walk into an open garage, you must START with the lights ON. If you don't want that feature and you want to turn it off, you must START with the lights OFF.

To turn the feature on, turn the lights on manually with the wall switch, then press and hold the LIGHT button for about 10 seconds until the motor unit light bulbs flash. Now, if the light bulbs are on, manually turn them out and then walk out through the open door. The light bulbs should come on.

To disable this feature, start with the light bulbs OFF and everything else is the same.