How is the exterior suffering?

How is the exterior suffering? In this Sutta series from SN 35.144 it says the following. Eye etc. and its objects are impermanence, not-self, and suffering. I understand all except that eye etc and its objects are suffering. For instance, if my eye arises as a result of a physical object, how is the physical object suffering? https://suttacentral.net/sn35.144/en/sujato