Journal of Clinical and Experimental Ophthalmology
Open Access

Abstract

Detecting the Physiological Blind Spot with Reaction Time Perimeter

Laura Knaapi, Eija Vesti and Markku T Leinonen

Objective: To study the ability of a novel reaction time perimeter to detect a physiological blind spot.
Methods: The location of the physiological blind spot of 11 healthy volunteers was determined with two independent methods, first by Octopus custom-made blind spot visual field program, and second by Fundus photography with a method previously described by the authors. With reaction time perimeter saccade triggering stimuli (STS) were shown in predetermined locations of the visual field in order to initiate saccades. An STS was followed by an FO (fixation object) i.e., an arrow head pointing either to the right or left at the same location as the previously shown STS. The recognition of the FO was reported by pressing a correct button (right or left respectively) thus verifying accurate fixation by the fovea. Time intervals between button presses were recorded. Reaction times for detecting the STS within the blind spot area were compared to those for detecting the STS in other locations of the visual field.
Results: Reaction times within the blind spot area were longer compared to those in other locations in 10 of 11 subjects (Analysis of variance), p<0.001 in 9 subjects, p<0.006 in one subject).
Conclusion: A physiological blind spot can be detected with reaction time perimeter.