Background: For nearly 75 years, optometric vision therapy has been an important mode of therapy for both children and adults who manifested a range of nonstrabismic accommodative and vergence disorders. Methods: In this article, the scientific basis for, and efficacy of, optometric vision therapy in such patients will be discussed. Using bio-engineering models of the oculomotor system as the conceptual framework, emphasis will be focused on studies that used objective recording techniques to directly assess therapeutically related changes in oculomotor responsivity. Results and Conclusions: The findings clearly support the validity of optometric vision therapy. Furthermore, the results are consistent with the tenets of general motor learning.

The scientific basis for and efficacy of optometric vision therapy in nonstrabismic accommodative and vergence disorders.

Purpose.This research quantified clinical measurements and functional neural changes associated with vision therapy in subjects with convergence insufficiency (CI).Methods.Convergence and divergence 4° step responses were compared between 13 control adult subjects with normal binocular visio

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Vision Therapy in Adults with Convergence Insufficiency: Clinical and Functional Magnetic Resonance Imaging Measures

Proximal contribution to a linear static model of accommodation and vergence

Accommodative dysfunction in individuals with mild traumatic brain injury (mTBI) can have a negative impact on quality of life, functional abilities, and rehabilitative progress. In this study, we used a range of dynamic and static objective laboratory and clinical measurements of accommodation to assess 12 adult patients (ages 18-40 years) with mTBI. The results were compared with either 10 control subjects with no visual impairment or normative literature values where available. Regarding the dynamic parameters, responses in those with mTBI were slowed and exhibited fatigue effects. With respect to static parameters, reduced accommodative amplitude and abnormal accommodative interactions were found in those with mTBI. These results provide further evidence for the substantial impact of mTBI on accommodative function. These findings suggest that a range of accommodative tests should be included in the comprehensive vision examination of individuals with mTBI.

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Accommodation in mild traumatic brain injury

Convergence and Divergence Exhibit Different Response Characteristics to Symmetric Stimuli

The disparity vergence eye movement system, long thought to be a simple continuous feedback system, has recently been shown to exhibit more complex dual-mode slow and fast responses. A model has been developed which simulates this behavior. The slow component accounts for the smooth following of slowly moving stimuli. The fast component has samnpling and prediction mechanisms which account for the staircase-like step responses to fast ramp stimuli. Model simulation responses to pulse, step, step-pulse, ramp, and sinusoidal stimuli show good fit to these diverse experimental results. This robust and comprehensive model forms the basis for further understanding of the dynamic controlling mechanisms of the vergence system.

Kenneth J. Ciufferda

Papers

A Dual-Mode Dynamic Model of the Vergence Eye Movement System