Volume 47 Number 3, 2010
Pages 183 — 200
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).