Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes

Summary

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.

Abstract

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements can be observed. VisualEyes2020 (VE2020) was developed based on the lack of customizable software-based visual stimulation available for researchers that does not rely on motors or actuators within a traditional haploscope. This new instrument and methodology have been developed for a novel haploscope configuration utilizing both eye tracking and autorefractor systems. Analysis software that enables the synchronized analysis of eye movement and accommodative responses provides vision researchers and clinicians with a reproducible environment and shareable tool. The Vision and Neural Engineering Laboratory's (VNEL) Eye Movement Analysis Program (VEMAP) was established to process recordings produced by VE2020's eye trackers, while the Accommodative Movement Analysis Program (AMAP) was created to process the recording outputs from the corresponding autorefractor system. The VNEL studies three primary stimuli: accommodation (blur-driven changes in the convexity of the intraocular lens), vergence (inward, convergent rotation and outward, divergent rotation of the eyes), and saccades (conjugate eye movements). The VEMAP and AMAP utilize similar data flow processes, manual operator interactions, and interventions where necessary; however, these analysis platforms advance the establishment of an objective software suite that minimizes operator reliance. The utility of a graphical interface and its corresponding algorithms allow for a broad range of visual experiments to be conducted with minimal required prior coding experience from its operator(s).

Introduction

Concerted binocular coordination and appropriate accommodative and oculomotor responses to visual stimuli are crucial aspects of daily life. When an individual has reduced convergence eye movement response speed, quantified through eye movement recording, doubled vision (diplopia) may be perceived^1,2. Furthermore, a Cochrane literature meta-analysis reported that patients with oculomotor dysfunctions, attempting to maintain normal binocular vision, experience commonly shared visual symptoms, including blurred/double vision, headaches, eye stress/strain, and difficulty reading comfortably³

Protocol

The study, for which this instrumentation and data analysis suite was created and successfully implemented was approved by the New Jersey Institute of Technology Institution Review Board HHS FWA 00003246 Approval F182-13 and approved as a randomized clinical trial posted on ClinicalTrials.gov Identifier: NCT03593031 funded via NIH EY023261. All the participants read and signed an informed consent form approved by the university's Institutional Review Board.

1. Instrumentation setup

Discussion

Applications of the method in research
Innovations from the initial VisualEyes2020 (VE2020) software include the expansibility of the VE2020 to project onto multiple monitors with one or several visual stimuli, which allows the investigation of scientific questions ranging from the quantification of the Maddox components of vergence¹⁸ to the influence of distracting targets on instructed targets¹⁹. The expansion of the haploscope system to VE2020 alon.......

Materials

Name	Company	Catalog Number	Comments
Analog Terminal Breakout Box	National Instruments	2090A
Convex-Sphere Trial Lens Set	Reichert	Portable Precision Lenses	Utilized for autorefractor calibration
Graphics Cards	-	-	Minimum performance requirement of GTX980 in SLI configuration
ISCAN Eye Tracker	ISCAN	ETL200
MATLAB	MathWorks	v2022a	AMAP software rquirement
MATLAB	MathWorks	v2015a	VEMAP software requirement
Microsoft Windows 10	Microsoft	Windows 10	Required OS for VE2020
Plusoptix PowerRef3 Autorefractor	Plusoptix	PowerRef3
Stimuli Monitors (Quantity: 4+)	Dell	Resolution 1920x1080	Note all monitors should be the same model and brand to avoid resolution differences as well as physical configurations