Nominal Ocular Hazard Distance (NOHD)

Nominal Ocular Hazard Distance (NOHD) is the distance from the source at which the intensity or the energy per surface unit becomes lower than the Maximum Permissible Exposure (MPE) on the cornea and on the skin.

The laser beam is considered dangerous if the operator is closer to the source than the NOHD.

The following tables provide the NOHD values for each sensor model and laser class, assuming continuous operation of the laser. As a configurable device, a sensor lets you set the laser exposure (laser on-time) independently of the frame period (total cycle time for data acquisition). Continuous operation of the laser means that the laser exposure is configured to be identical to the frame period, which is also referred to as 100% duty cycle. However, in many applications the laser exposure can be smaller than the frame period (less than 100% duty cycle), thereby reducing the NOHD. The tables therefore show the worst-case NOHD.

In the model numbers in the following tables, an "x" refers to any number that represents an existing model. So for example, 2x80D refers to Gocator 2180, 2380, and 2880 (but not, for example, 2480, which isn't available).

The following table provides NOHD values for current hardware versions of sensors.

Current Hardware Versions

Model	Laser Class	Wavelength (nm)	Class I NOHD (mm)	Class II NOHD (mm)
21x0D/23x0D (except 2x80D)	2	660	670	-
	3R	660	3340	1330
2x80D	2	660	1310	-
	3R	660	4700	1850
2350C	3B (NIR laser)	808	19750	-
2375C	3B (NIR laser)	808	13777	-
2x75D	2	660	670	-
	3R	660	3340	1330
2410A 2420A	2M	405	259 a	103 a
	3R	405	1300 a	500 a
2430A 2440A	2	660	670	-
	3R	660	3340	1330
	3B	660	6661	2598
2430A 2440A	2	405	554	-
	3R	405	2770	1065
	3B	405	7546	3005
2450A	2	405	559	-
	3R	405	2794	1075
	3B	405	9433	3755
2490A	2	660	1310	-
	3R	660	4700	1850
251xA	2	405	615a	-
252xA	2	405	615a	-
2530A	2	405	564a	-
2540A 2550A	2	405	590a	-
	3R	405	2949a	1150
	3B	405	6667a	2600
2630A 2640A 2650A 2670A	2	405	615a	-
	3R	405	3078a	1200
	3B	405	6667a	2600
2690A	2	660	718a	-
	3R	660	3590a	1400
	3B	660	6667a	1700

^a With exposure time < 10 seconds. For longer exposure times, consult IEC 60825.