Pupil Perimetry
The TFA combines advanced multi-focal stimulus and analysis methods with real time computer vision pupil monitoring to realize the dream of objective pupil perimetry. Initially developed over 15 years ago (i) and subsequently demonstrated in multiple laboratories (ii), pupil perimetry is based on measuring involuntary pupil diameter changes in response to retinal visual stimulation.
By combining advanced sparse stimuli (iii), regressive multi-focal methods (iv) and automated real-time computer vision pupil monitoring, the TFA moves pupil perimetry from the laboratory into clinical practice.
A single frame from the Standard O30-44 Stimulus Ensemble. Note the independent frames are designed for dichoptic presentation to the left and right eyes which are fused by the subject in a single cyclopean view of the patterns. The outer circles (indicating the field of view limits of ±30° radius) have been added to these images for clarity. The following image shows this stimulus frame as perceived by the patient
Example videos
The TFA Stimulus post shows a video that illustrates the standard TFA Stimulus Pattern (as described above), and the TFA Pupil Responses post shows a video of typical pupil responses to the TFA Stimulus.
Visual Fields and Pupil Dynamics
The TFA compares a subject’s performance against a normative database and generates bilateral visual field test results in a format familiar to the clinician. Initial training for both clinicians and technicians is minimal with prior experience of standard perimeters being directly relevant.
In addition to creating standard reports that are familiar and easy to interpret, the TFA report includes details of the patient’s pupil dynamics (image at right). These test results indicate the relative performance of the direct and consensual responses, and can indicate a range of neurological issues that may warrant further investigation.
The TFA report details the dynamic behavior of each pupil and characterizes the input from both the direct retina (shown as the “D” bar graphs) and the consensual retina (the “C” bar graphs). The values are given in terms of the deviation from normal. Disparities between the 4 values may indicate a variety of pupil or neural issues that may warrant further investigation.
