Name: quantification of oculomotor responses and accommodation through instrumentation and analysis toolboxes
Uploaded: 2023-03-03T13:40:00
Description: Watch this Scientific Journal Video about Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes at JoVE.com

This research was supported by National Institutes of Health grant R01EY023261 to T.L.A. and a Barry Goldwater Scholarship and NJIT Provost Doctoral Award to S.N.F.

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&#39;s Institutional Review Board.
1. Instrumentation setup</...

<ol>
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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photorefraction+estimates+of+refractive+power+varies+with+the+ethnic+origin+of+human+eyes.">Photorefraction estimates of refractive power varies with the ethnic origin of human eyes.</a> Scientific Reports. 5, 7976 (2015).</li><li>Maddox, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Clinical Use of Prisms and the Decentering of Lenses. , (1893).</li><li>Yaramothu, C., Santos, E. M., Alvarez, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+visual+distractors+on+vergence+eye+movements.">Effects of visual distractors on vergence eye movements.</a> Journal of Vision. 18 (6), 2 (2018).</li><li>Borsting, E., Rouse, M. W., De Land, P. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospective+comparison+of+convergence+insufficiency+and+normal+binocular+children+on+CIRS+symptom+surveys.+Convergence+Insufficiency+and+Reading+Study+(CIRS)+group.">Prospective comparison of convergence insufficiency and normal binocular children on CIRS symptom surveys. Convergence Insufficiency and Reading Study (CIRS) group.</a> Optometry and Vision Science. 76 (4), 221-228 (1999).</li><li>Maxwell, J., Tong, J., Schor, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+first+and+second+order+dynamics+of+accommodative+convergence+and+disparity+convergence.">The first and second order dynamics of accommodative convergence and disparity convergence.</a> Vision Research. 50 (17), 1728-1739 (2010).</li><li>Alvarez, T. 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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...

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 perceived1,2. 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. Rapid conjugate eye movements (saccades), when deficient, can under-respond or over-respond to visual targets, thus meaning further sequential saccades are required to correct this error4. These oculomotor responses can also be confounded by the accommodative system, in which the improper focusing of light from the lens creates blur5. 
Tasks such as reading or working on electronic devices demand coordination of the oculomotor and accommodative systems. For individuals with binocular eye movement or accommodative dysfunctions, the inability to maintain binocular fusion (single) and acute (clear) vision diminishes their quality of life and overall productivity. By establishing a procedural methodology for quantitatively recording these systems independently and concertedly through repeatable instrumentation configurations and objective analysis, distinguishing characteristics about the acclimation to specific deficiencies can be understood. Quantitative measurements of eye movements can lead to more comprehensive diagnoses6 compared to conventional methods, with the potential to predict the probability of remediation via therapeutic interventions. This instrumentation and data analysis suite provides insight toward understanding the mechanisms behind current standards of care, such as vision therapy, and the long-term effect therapeutic intervention(s) may have on patients. Establishing these quantitative differences between individuals with and without normal binocular vision may provide novel personalized therapeutic strategies and heighten remediation effectiveness based on objective outcome measurements.
To date, there is not a single commercially available platform that can simultaneously stimulate and quantitatively record eye movement data with corresponding accommodative positional and velocity responses that can be further processed as separate (eye movement and accommodative) data streams. The signal processing analyses for accommodative and oculomotor positional and velocity responses have respectively established minimum sampling requirements of approximately 10 Hz7 and a suggested sampling rate between 240 Hz and 250 Hz for saccadic eye movements8,9. However, the Nyquist rate for vergence eye movements has yet to be established, though vergence is about an order of magnitude lower in peak velocity than saccadic eye movements. Nonetheless, there is a gap in the current literature regarding eye movement recording and auto-refractive instrumentation platform integration. Furthermore, the ability to analyze objective eye movement responses with synchronous accommodation responses has not yet been open-sourced. Hence, the Vision and Neural Engineering Laboratory (VNEL) addressed the need for synchronized instrumentation and analysis through the creation of VE2020 and two offline signal processing program suites to analyze eye movements and accommodative responses. VE2020 is customizable via calibration procedures and stimulation protocols for adaptation to a variety of applications from basic science to clinical, including binocular vision research projects on convergence insufficiency/excess, divergence insufficiency/excess, accommodative insufficiency/excess, concussion-related binocular dysfunctions, strabismus, amblyopia, and nystagmus. VE2020 is complemented by the VEMAP and AMAP, which subsequently provide data analysis capabilities for these stimulated eyes and accommodative movements.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Analog Terminal Breakout Box</td>
			<td>National Instruments</td>
			<td>2090A</td>
			<td></td>
		</tr>
		<tr>
			<td>Convex-Sphere Trial Lens Set</td>
			<td>Reichert</td>
			<td>Portable Precision Lenses</td>
			<td>Utilized for autorefractor calibration</td>
		</tr>
		<tr>
			<td>Graphics Cards</td>
			<td>-</td>
			<td>-</td>
			<td>Minimum performance requirement of GTX980 in SLI configuration</td>
		</tr>
		<tr>
			<td>ISCAN Eye Tracker</td>
			<td>ISCAN</td>
			<td>ETL200</td>
			<td></td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>MathWorks</td>
			<td>v2022a</td>
			<td>AMAP software rquirement</td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>MathWorks</td>
			<td>v2015a</td>
			<td>VEMAP software requirement</td>
		</tr>
		<tr>
			<td>Microsoft Windows 10</td>
			<td>Microsoft</td>
			<td>Windows 10</td>
			<td>Required OS for VE2020</td>
		</tr>
		<tr>
			<td>Plusoptix PowerRef3 Autorefractor</td>
			<td>Plusoptix</td>
			<td>PowerRef3</td>
			<td></td>
		</tr>
		<tr>
			<td>Stimuli Monitors (Quantity: 4+)</td>
			<td>Dell</td>
			<td>Resolution 1920x1080</td>
			<td>Note all monitors should be the same model and brand to avoid resolution differences as well as physical configurations</td>
		</tr>
	</tbody>
</table>

quantification of oculomotor responses and accommodation through instrumentation and analysis toolboxes

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&#39;s (VNEL) Eye Movement Analysis Program (VEMAP) was established to process recordings produced by VE2020&#39;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).

Group-level ensemble plots of stimulated eye movements evoked by VE2020 are depicted in Figure 11 with the corresponding first-order velocity characteristics.
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/64808/64808fig11.jpg" /> 
Figure 11: Eye movement response ensembles. The ensemble plots of vergence steps (left) and saccades (right) stimulated using th...

Watch this Scientific Journal Video about Quantification of Oculomotor Responses and Accommodation Through Instrumentation and Analysis Toolboxes at JoVE.com

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.

Through the purposeful stimulation and recording of eye movements, the fundamental characteristics of the underlying neural mechanisms of eye movements ...

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