Symptoms associated with binocular vision disorders are attributed to stress on the disparity vergence system. This system is composed of an open-loop burst signal that initiates changes in the ocular vergence angle, and a closed-loop sustained response that completes and maintains this angle. Disparity vergence also contains an adaptable component known as phoria adaptation (PA). The ability of the sustained response to generate PA has been extensively studied, however little is known regarding the burst signal's contribution to PA. The phoria is the ocular angle in the absence of a disparity vergence response. However the time course for depleting PA makes measuring the true phoria challenging and is typically done by extended periods of monocular occlusion. As these extended periods of occlusion are not practical in a clinical setting, two forced vergence cover test (FVCT) procedures have previously been proposed for rapidly depleting PA and revealing the true phoria. In a series of experiments, this study evaluated these FVCT procedures and the burst vergence contribution to PA. The FVCTs were performed before and after significant PA was generated by fifteen minutes of binocularly viewing through base-out prisms. Pre- and post-adaptation FVCT results were significantly different (p<0.01) indicating that the procedures did not eliminate existing phoria adaptation. In a second experiment, PA generated in response to three over-convergence adapting scenarios was measured. These scenarios consisted of 30-seconds of steady fusion (steady), 3-seconds of fusion (quick-step), 27-seconds of a flashed target presentation (flash) that repeatedly presented the stimuli binocularly when subjects were under-converged, and monocularly when subject's vergence angle was near that required of the stimuli; the flash period concluded with 3-seconds of fusion. The flash period was designed to generate repeated burst vergence responses with minimal influence from the closed-loop response. Greater PA was generated by the flash period than the quick-step (p=0.025). Equivalent PA was found following the flash and the steady periods. In conclusion, currently described FVCT procedures do not eliminate PA and thus are unlikely to reveal the true phoria. Additionally, the burst vergence response can generate significant PA. Advisors/Committee Members: Fogt, Nicklaus (Advisor).