Iris Shaders recently updated to 1.7.0, introducing shader compatibility with Distant Horizons 2.1, a mod that adds LODs, or levels-of-detail rendering, to Minecraft. It would be a fun surprise to see DH compatibility added to Super Duper Vanilla shaders, but as of now, attempting to use it with DH results in the LODs being completely invisible.

Hello, while it is being planned, I am currently very busy with schoolwork and limited specs for using the mod unfortunately. I will however keep this post open until it is finally implemented.

Hello, here are the issues I've found so far.

LOD water renders on top of everything, regardless of the settings, while regular water doesn't :

Shadows are blocky. Maybe because these are "LOD shadows" or something? Player shadows are unaffected.
Some blocks deep underground also render on top of everything :