Way way back in 2013
during my short stint up in Ohio, GHURD and when Rich and I made the trek to Philippines in 2010 , it really was interesting to see (pun intended) how well the human eye adjusts to lower light levels.
On both we were able to take 20ma LEDs down to 15ma before there was any perceived differences.
When a home's only source of light is a 12V/7Ah battery that gets charged from a 10 or 17 watt Solar panel , the saving adds up.
The picture I posted up here of the 80y/o lady was one of those defining moments.
To this day a spec my LED lights at 15ma instead of pushing them too much.
Cassy's LED master class remains on this forum if you are so inclined to read up on it.