You searched for:
“photoptometry”
photoptometry
Measurement of the least illumination required for eyesight.
This entry is located in the following units:
meter-, metro-, metr-, -metrical, -metrically, -metron, -metric, -metrist, -meter, -meters, -metry, -metre
(page 31)
photo-, phot-, -photic
(page 13)