The title is a bit misleading though. Though it would be real cool, saying we can detect molecule size pattern does not mean we could read Braille alphabet on molecule size dots.
The eye can detect nanometer size patterns: we can make the difference between blue light ( radiation with a 400 nanometers wave length ) and red light ( radiation with a 800 nanometers wave length ). Does not mean we can see nanometer size objects. Bottom line, be careful talking about patterns ....
I make telescope mirrors. The error I'm allowed is 100 nm. I would love to just drag my fingers over the glass and tell if something is not quite right with the optical surface. In reality, I need a pretty elaborate optical setup to amplify the errors about 1/2 million times, in order to see them.
I'm guessing the spatial frequency of the pattern in that experiment is on the same size scale like the vertical amplitude of it.
We can also see a candle in complete darkness from 50 km away so just a handful of photos are enough for a sensation.
"The researchers found that the emission of only 90 photons could elicit visual experience. However, only 45 of these actually entered the retina, due to absorption by the optical media. Furthermore, 80% of these did not reach the fovea. Therefore, the human eye can detect as few as nine photons."