Abstract: A binocular pupillometer apparatus is provided with processing means to calculate the relative afferent pupillary defect (RAPD) in a subject. The RAPD is calculated as the shift required to bring the two pupillary responses of the left and right eyes into coincidence. Where the responses are not parallel, modified pupillary responses are determined having the same area difference between the responses and an average rate of change with respect to stimulation intensity. The RAPD is calculated from the modified pupillary responses rather than the observed responses. Improvements to the pupillometer include a divider positioned between the left and right stimulating channels.
Abstract: Pupillometric apparatus for assessing pupillary near reflex in a subject incorporates a visible fixation point which is moveable between near and far positions and which is viewable through an eyepiece via an accomodation lens positioned between the eyepiece and the near position. The focal length of the accomodation lens exceeds the distance of the lens from both the near and far positions of the fixation point, so that the subject always observes virtual images in respect of the fixation point. In this way the distance between observed virtual positions of the fixation point at its near and far positions exceeds the actual distance between these positions. Binocular pupillometric apparatus in which images of the left and right pupils of a subject are rapidly and alternately transmitted to the same part of a single image sensor and signal data so obtained are processed to generate separated image data representative of the dimensions of the left and right pupils is also disclosed.
Type:
Grant
Filed:
September 23, 2005
Date of Patent:
December 1, 2009
Assignee:
Procyon Instruments Limited
Inventors:
Daniel Robert Stafford Taylor, Alan Thomas Cayless
Abstract: Pupillometric apparatus for assessing pupillary near reflex in a subject incorporates a visible fixation point which is moveable between near and far positions and which is viewable through an eyepiece via an accomodation lens positioned between the eyepiece and the near position. The focal length of the accomodation lens exceeds the distance of the lens from both the near and far positions of the fixation point, so that the subject always observes virtual images in respect of the fixation point. In this way the distance between observed virtual positions of the fixation point at its near and far positions exceeds the actual distance between these positions. Binocular pupillometric apparatus in which images of the left and right pupils of a subject are rapidly and alternately transmitted to the same part of a single image sensor and signal data so obtained are processed to generate separated image data representative of the dimensions of the left and right pupils is also disclosed.