Visual acuity tester
First Claim
1. A device for measuring visual acuity both under normal conditions as well as following medical or visual stress comprisingmeans for projecting a moving spot of light in the view of a subject,means for attenuating the intensity of said spot of light,eye tracking means for sensing the position of the eyes of the subject while said spot of light is present,difference means for comparing the position of the eyes of the subject and the position of said spot of light, including detector means for sensing divergence therebetween,converter means for converting said intensity of said spot of light at the instance of said divergence, to visual acuity units, anddisplay means for displaying the output of said converter means.
2 Assignments
0 Petitions
Accused Products
Abstract
A device for objectively determining visual acuity includes a viewing screen on which a moving spot of light of diminishing intensity is projected. Infrared eye tracking sensors scan the eyes of the subject and generate a voltage analog signal of the eyes'"'"' position. The position signal is compared with a signal representing the position of the moving spot, and the difference is fed to a threshold detector circuit. As the spot becomes too dim to be seen by the subject, the eyes fail to track the spot, and the difference between the two signals surpasses the threshold of the detector circuit. The brightness of the spot when last tracked successfully, which correlates with standard visual acuity measurements, is then displayed as the visual acuity of the subject.
-
Citations
9 Claims
-
1. A device for measuring visual acuity both under normal conditions as well as following medical or visual stress comprising
means for projecting a moving spot of light in the view of a subject, means for attenuating the intensity of said spot of light, eye tracking means for sensing the position of the eyes of the subject while said spot of light is present, difference means for comparing the position of the eyes of the subject and the position of said spot of light, including detector means for sensing divergence therebetween, converter means for converting said intensity of said spot of light at the instance of said divergence, to visual acuity units, and display means for displaying the output of said converter means.
Specification