Author ORCID Identifier
0000-0002-2739-2759
Document Type
Dissertation
Date of Award
5-31-2025
Degree Name
Doctor of Philosophy in Biomedical Engineering - (Ph.D.)
Department
Biomedical Engineering
First Advisor
Tara L. Alvarez
Second Advisor
Xiaobo Li
Third Advisor
Chang Yaramothu
Fourth Advisor
Qinyin Qiu
Fifth Advisor
Suril Gohel
Sixth Advisor
Mitchell Scheiman
Abstract
Concerted binocular coordination evoking oculomotor and refractive responses to visual stimuli are essential to daily function. Oculomotor dysfunctions can inhibit binocular responses to visually-near stimuli and have high comorbidities to accommodative dysfunctions. Three visual cues for inward (convergent) and outward (divergent) oculomotor movements, when presented concertedly create natural-viewing conditions: disparity- the binocular difference in light cast onto the fovea due to differing ocular perspectives, blur- the acuity of a visual target which stimulates accommodation, and proximal- the perceived distance of a visual stimuli based on size.
This study aims to quantitatively investigate oculomotor vergence and accommodation performances between individuals with binocularly normal vision (BNV) and typically occurring convergence insufficiency (TYP-CI). To evaluate the isolated and combinatory contributions of these vergence cues, participants were monocularly, or binocularly, presented stimuli at visual-near (40 cm) and visual-far utilizing (1 m) distances within a haploscope configuration paired with a dynamic autorefractor. For each cohort, 50 participants were recorded longitudinally before and after office-based vergence and accommodative therapy. Files containing significant signal loss were omitted. Subsequently, 31 participants with BNV were analyzed, alongside 28 patients with TYP CI. The Accommodative Movement Analysis Program (AMAP) custom analysis software was developed to evaluate the recorded data for temporal, positional, and velocity differences in accommodative and gaze vergence. Following intra-subject and inter-subject outlier removal, one-way between-subjects Welch's ANOVA's and between-groups independent samples t-tests were performed.
Significant differences were observed in the accommodative dynamics for isolated and combinatory cue-conditions. Combinatory blur and foveal-disparity cue responses, with a diminished proximal cue, demonstrated comparable responses behaviors compared to natural-viewing conditions. The selective diminishment of blur or disparity led to significant reductions in the positional response magnitudes and velocity metrics. However, in isolation, the blur cue contributed significantly more to the final accommodative response strength than the foveal-disparity cue. The proximal cue provided minimal contributions to accommodative response. Comparative performances between the BNV and TYP-CI cohorts for blur and disparity, as well as blur and proximal stimuli correlate with the underperformance of the oculomotor and accommodative system in TYP-CI patients. These analyses suggest that the neural crosslinking between the oculomotor and accommodative systems may have weakened influences on each system. This is potentially due to poor convergent induced accommodation or underperforming accommodation lessening oculomotor feedback and increasing visual task-based stressors.
Future implementations and improvements from the results of this work can continue to add to the insight and elucidation of how therapeutic interventions for accommodative and oculomotor dysfunctions are intrinsically coupled and/or selectively decoupled through the viewing conditions of common daily life.
Recommended Citation
Fine, Sebastian, "The interplay of accommodation and oculomotor vergence within young adults with binocularly normal vision and typically-occurring convergence insufficiency" (2025). Dissertations. 1833.
https://digitalcommons.njit.edu/dissertations/1833
Included in
Biomedical Commons, Optometry Commons, Rehabilitation and Therapy Commons, Vision Science Commons
