Journal of Rehabilitation Research & Development (JRRD)

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Volume 47 Number 3, 2010
   Pages 183 — 200

Accommodation in mild traumatic brain injury


Appendix: Glossary of Relevant Ophthalmic Terminology
Wesley Green, MS et al.


AC/A ratio: The change in accommodative convergence (AC) for a given change in accommodation (A).

Accommodative amplitude: The maximum response level; closest point of clear focus.

Accommodative facility: The number of cycles to pre-selected accommodative stimulus changes over a specified period of time.

Accommodative stimulus/response function (AS/R): The overall accommodative response profile for a range of accommodative stimuli. Linear regression analysis is then performed to determine the slope of the aggregate responses.

Gain: The ratio of the response amplitude to the stimulus amplitude.

Heterophoria: The position of the eyes in the absence of fusion.

NRA: Negative relative accommodation; the amount of decrease in accommodation during binocular viewing, while maintaining the vergence response relatively constant.

Peak velocity: The maximum velocity of a response.

PRA: Positive relative accommodation; the amount of increase in accommodation during binocular viewing, while maintaining the vergence response relatively constant.

Steady-state variability: The response variation once the target is acquired and sustained on the foveas.

Time constant: The time for an exponential response to reach 63% of its final amplitude.

Tonic accommodation: The focusing state of the eye in the absence of blur, disparity, or proximity (e.g., the optical state of the eye in total darkness).


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