Table 1.

Estimated corneal illuminance provided by the LRC, RPI

Assumed applicationEstimated corneal illuminance, lux
D: darkness, suburban night sky0.2
O: other artificial light sourcea10
H: halogen lamp residence20
I: incandescent light residence20
F: fluorescent lamp office100
N: natural light (indoors)200
S: sunlight, natural light (outdoors)2,000
  • aMostly low light levels like TV in otherwise dark room, or candle light, or PC (information from diaries).