Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes

VisualEyes2020 (VE2020) is a custom scripting language that presents, records, and synchronizes visual eye movement stimuli. VE2020 provides stimuli for conjugate eye movements (saccades and smooth pursuit), disconjugate eye movements (vergence), accommodation, and combinations of each. Two analysis programs unify the data processing from the eye tracking and accommodation recording systems.

The software packages used in this study provide comprehensive and complete control over any given experiment of interest. Visualize 2020 customizes stimulation, AMAP and VMAP provide complimentary analysis of accommodative and ocular motor behaviors respectively. Transparency is the main advantage of this technique.

Programmatically, stimulus behavior, calibration routine and analytical processes can be user defined for any given experimental protocol within the software scopes. The objective measurement of eye movements and accommodation with data analytics empowers vision scientists and physicians to first be able to tell the difference between patients with binocular dysfunction and binocular neuroma controls. And second, be able to understand the underlying neuro mechanism of vision therapeutics.

Eye moment recordings can be used as a potential biomarker for ocular motor dysfunctions, and they have potential applications in the concussion and Parkinson's disease population that have a high comorbidity of binocular vision dysfunctions. Begin by monitoring the connections and hardware of the setup. The VisualEyes 2020 system assigns the monitors spatially and clockwise order.

Ensure the proper spatial configuration of the stimulus monitors. The primary control monitor is indexed as zero and all the successive monitors are indexed from one onwards. Select Identify to visualize the assigned monitor indices for each stimulus display connected to the control computer.

In the display monitor settings, navigate to Display resolution and check the recommended resolution. Ensure the eye tracking system is on the optical midline with a minimum camera distance of 38 centimeters. Check that the autorefractor system is on the optical midline and approximately one meter from the eyes.

Validate the configuration of the hardware and equipment by referencing the dimensions. Ensure the desktop and corresponding eye tracking hardware are configured and calibrated according to the manufacturer's instructions. Monocularly occlude the participants'left eye with an infrared transmission filter and place a convex sphere trial lens in front of the filter.

Next, binocularly present a high acuity four degree stimulus from the physically near stimulus monitors. Then binocularly present a high acuity 16 degree stimulus from the physically near stimulus monitors. Once informed consent is acquired direct the participant to be seated in the haploscope.

Position the participant's forehead and chin against a fixed headrest to minimize head movement and adjust the chair height so that the participant's neck is comfortable for the entire experiment. Adjust the eye movement recording cameras to ensure the participant's eyes are capturable within the cameras field of view. Then, adjust the eye tracking signal and the eye tracking gating gains to capture anatomical features such as the limbus, pupil and corneal reflection.

Validate the capture of the eye movement data by asking the participant to perform repeated vergence or saccadic movements. To configure the data, utilize the external storage device that contains the autorefractor data and export the data to a device with the AMAP installed. Start the AMAP application and select either file pre-processor or batch pre-processor.

Check the AMAPs progress bar and notifications as the system provides these when the selected data have been pre-processed. Folder directories are generated from the AMAPs pre-processing for data processing transparency, and accessibility through the computer's local drive under AMAP output. If an AMAP feature is selected without prior data processing check for a file explorer window that appears for the user to select a data directory.

Next, to perform the AMAP data analysis, select a data file to analyze through the Load Data button which loads any available files into the current file directory, defaulted to a generated AMAP underscore output folder. The selected data file name appears in the current file field. Under the Eye Selector, check the default selection which presents binocularly averaged data for the recorded accommodative refraction.

Switch the data type between accommodative refraction and oculomotor vergence, denoted as Gaze through the Type Selector. Check further graphical customizations available to present the data metrics and first order and second order characterizations. Check the default metrics for the AMAP.

After displaying the graphical options perform modifications to the response starting index, response ending index and peak velocity index through the metric modification spinners. Following the analysis of all the recorded movements displayed, save the analyzed metrics for each data file in the movement ID field, or through the left word and right word navigation arrows. Unanalyzed movements have a default classification of not a number denoted as NaN, and are not saved or exported.

Perform manual classification as good or bad for each movement to ensure complete analysis by any operator. Select the Save button to save the analyzed data. Then select the Export button to export the analyzed data to an accessible spreadsheet that contains individual movement metrics and the averaged exported metrics sheets.

Group level ensemble plots of stimulated eye movements evoked by VisualEye 2020 are depicted here with the corresponding first order velocity characteristics. Each eye movement position trace is plotted as a uniquely colored line and overlaid with the group level velocity response in red. The visualization of the participant performances can also be accomplished with the AMAP, which shows an ensemble of five degrees convergent responses and the corresponding 1.5 diopter accommodative responses resulting from data processing.

It is critical that a participant is centered on the midline and they understand what they need to do with their eyes for the experiment. Clear eye images with appropriate gating are critical to record data that can be analyzed offline. We're exploring new technologies such as virtual reality to translate these techniques into portable devices that are for diagnostic and therapeutic interventions to help patients with binocular dysfunction, which is common in the general population after a concussion or for patients with Parkinson's disease.