Question on changes to programs/web sites to accommodate retina display

I am not as versed on the topic as some of you might be so please excuse if this is a stupid question. My question is this, when adobe, web sites, and other programs make changes to accommodate Apple's retina display resolution, how will the change effect non-retina displays [will it merely be a matter of users adjusting the resolution on non-retina computers, or is there a code in the programs that instruct a computer to automatically recognize a particular resolution setting]? It just seems if there are changes for retina those changes will have a reverse negative effect on non-retina displays.