This paper; https://arxiv.org/abs/1701.03418, Direct Probe of Dark Energy through Gravitational Lensing Effect, addresses a potential means to measure dark energy over cosmological distances. Perhaps I am a bit slow, but, I found the basic idea sufficiently simple and obvious that I am surprised it hasn't been suggested before. Perhaps it was, and it merely eluded my attention. I feel flooded with questions I cannot yet even fully articulate. A couple which have surfaced include - 1] How might reverse lensing due to DE impact the apparent angular size of remote structures in the universe? 2] How might this affect the Friedmann equations?