This utility use the Unity camera property called "layerCullDistances" to cull objects in 3d space. You just have to assign to your objects your own layers and use this utility to assign a distance (it's layer based). It can make a huge impact in your project's frame rate if used properly.
This project uses one demo scene to show the purpose of this utility and see it in action.
There is an old youtube video explaining how to use it (in spanish, sorry). https://www.youtube.com/watch?v=fyVdX6DxJNw
It should work in any Unity version.
Unity project and source code license: MIT License.