Nyctalopia or night blindness is described as the inability for the subjects eyes to adapt to dark conditions. There are a number conditions associated with night blindness including a lack of vitamin A. The Adaptometer was developed by researchers at Johns Hopkins University and the Instrument Development Group to quantify pupillary response and hence predict vitamin A deficiency.

The custom designed headset incorporates a CCD camera element and a solid state flash. The patient’s eyes are subjected to a flash of white light subsequent to allowing them to adjust to dark conditions. Custom developed software processes video images pre-flash and post-flash to quantify the patient’s pupillary light reflex