Table 2. Overview of the classes of photodamage to the retina

  Class I damage
(Noell damage)
Class II damage
(Ham damage)
Exposure duration > 1.5 hours < 4 hours
Retinal irradiance < 1 mW/cm2 > 1 mW/cm2
Source spectrum Incandescent white White and laser lines
Primary investigated animal
Rats Primates
Anesthesia No Typically yes
Size of exposure source Large Small
Site of major impact Photoreceptors RPE


Source: SCENIHR, Health effects of artificial light, 19 March 2012,
 3.4.3 Biological effects, pp. 31-38.