barkalyle'o lujvo

l1=b1 is a monocle/pair of (eye)glasses/spectacles allowing the clear sight of l2 (light) by k2 (wearer).

Cf. lenjo, kanla, bartu, le'otci, vistci.

In notes:

darvistci
t1 is a telescope for seeing v2=d1 which is far from d2.
le'otci
t1 is a monocle/pair of (eye)glasses/spectacles for observational activity t2.
vistci
t1 is an optical tool used by v1 to see v2.