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You searched for subject:(phoria adaptation). Showing records 1 – 2 of 2 total matches.

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The Ohio State University

1. McDaniel, Catherine E. Phoria Adaptation in Clinical Vergence Testing.

Degree: MS, Physiological Optics, 2008, The Ohio State University

Phoria adaptation (PA) helps maintain the vergence posture during near work. Vergence facility (VFAC) and vergence ranges (VRAN) are said to assess different aspects of the vergence eye movement system. The purpose of this experiment was to measure vergence adaptation following VFAC and VRAN testing to more fully understand the role of PA in vergence testing. 30 subjects participated in two testing sessions. In each, the modified Thorington card was used to measure the phoria before and after testing: VRAN and VFAC. PA occurred with VRAN and VFAC testing. The results from VRAN and VFAC do not correlate. The effect of PA on test results was different. For VRAN, those who passed had significantly more PA than those who did not. This was not true for VFAC testing. These results again suggest that VRAN (slow fusional vergence) and VFAC (fast fusional vergence) assess different aspects of the fusional vergence system Advisors/Committee Members: Fogt, Nicklaus (Advisor).

Subjects/Keywords: Ophthalmology; phoria adaptation; vergence facility

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

McDaniel, C. E. (2008). Phoria Adaptation in Clinical Vergence Testing. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1211507915

Chicago Manual of Style (16th Edition):

McDaniel, Catherine E. “Phoria Adaptation in Clinical Vergence Testing.” 2008. Masters Thesis, The Ohio State University. Accessed April 16, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211507915.

MLA Handbook (7th Edition):

McDaniel, Catherine E. “Phoria Adaptation in Clinical Vergence Testing.” 2008. Web. 16 Apr 2021.

Vancouver:

McDaniel CE. Phoria Adaptation in Clinical Vergence Testing. [Internet] [Masters thesis]. The Ohio State University; 2008. [cited 2021 Apr 16]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1211507915.

Council of Science Editors:

McDaniel CE. Phoria Adaptation in Clinical Vergence Testing. [Masters Thesis]. The Ohio State University; 2008. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1211507915


The Ohio State University

2. Toole, Andrew J. The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation.

Degree: PhD, Physiological Optics, 2008, The Ohio State University

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).

Subjects/Keywords: Ophthalmology; phoria; phoria adaptation; vergence; vergence adaptation; cover test; forced vergence cover test; burst vergence response

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Toole, A. J. (2008). The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1211893739

Chicago Manual of Style (16th Edition):

Toole, Andrew J. “The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation.” 2008. Doctoral Dissertation, The Ohio State University. Accessed April 16, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1211893739.

MLA Handbook (7th Edition):

Toole, Andrew J. “The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation.” 2008. Web. 16 Apr 2021.

Vancouver:

Toole AJ. The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation. [Internet] [Doctoral dissertation]. The Ohio State University; 2008. [cited 2021 Apr 16]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1211893739.

Council of Science Editors:

Toole AJ. The Effects of Forced Vergence Cover Tests and the Burst Vergence Response on Phoria Adaptation. [Doctoral Dissertation]. The Ohio State University; 2008. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1211893739

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