Crime-lite® Eye

Darkness Adpatation Checker


The Foster + Freeman ‘Crime-lite® Eye’ is a simple pocket-sized device that helps crime scene examiners to achieve optimum dark adaptation when entering a dark environment to search for evidence using a forensic light source.

During darkness adaptation, as the brain attempts to interpret and understand its surroundings, an examiner’s vision suffers from low acuity and greatly reduced colour sensitivity. As a result of this, the examiner’s ability to detect faint fluorescence, stimulated by a forensic light source, is significantly reduced.


A 2013 study by the UK Centre for Applied Science and Technology (CAST) demonstrated that examinations conducted without proper dark adaptation would result in evidence being missed.


A visual guide to when full darkness adaptation has been achieved

Using the Crime-lite Eye is easy. A numerical LED display shows the numbers 1-20 to indicate varying degrees of illumination intensity (from 1 very-dim to 20 very-bright).

Having determined in advance a sensitivity level that is considered fit to commence an examination (this level may be governed by the individual or at organisation level) the examiner needs only to use the Up and Down arrows to select the desired sensitivity level (1-20) and then, upon entering the dark environment, wait until the chosen sensitivity level is reached.

Once the selected level becomes visible, darkness adaptation has been achieved.


Dark Adaptation Goggles can reduce adaptation times

By wearing a pair of red-glass viewing goggles it is possible to dark adapt the eye prior to fluorescent examinations. The goggles may also be worn when moving between dark and light environments to ensure that the eye remains dark adapted.

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