Samsara is a psychological condition, not a physical one.
Our perception is limited not by the external matter or senses, but by our psychological condition. If you remove the psychological conditioning, your perceptions expand to the full power of each sense.
Our physical senses are capable of perceiving far more than we currently do. The problem is not the senses, it is the state of the consciousness that uses them.
If you liberate the consciousness, your senses can be utilized fully. Moreover, non-physical senses can also be empowered, giving perception of non-physical aspects of nature.
In short, currently we do not see what is right in front of us.
The living creatures of other aspects or dimensions of nature have more modes of existence than can easily be explained, ranging from the densest to the most subtle and formless (even physically, there is an incredible range of creatures). Yes, those levels are right here, right now, but beyond our current abilities to see. In the ancient past, humanity could see them. The future humanity will too. To gain that ability now, one must extract the consciousness from its psychological cages, and power it with a lot of energy.
The Bhavachakra course touches on some of this.
"Do not worry; cultivate the habit of being happy." - Samael Aun Weor