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 species	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.