accommodative convergence: accommodation ratio

ac·com·mo·da·tive con·ver·gence: ac·com·mo·da·tion ra·ti·o

(AC:A) (ă-kom'ŏ-dā'tiv kŏn-vĕr'jĕns ă-kom'ŏ-dā'shŭn rā'shē-ō)
The amount of convergence (measured in prism diopters of convergence) divided by the amount of accommodation (measured in diopters) required to direct both eyes on an object.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
(19) As always when prescribing prism, care must be taken to balance the refractive and prismatic prescriptions with respect to the accommodative convergence: accommodation ratio. (18) Accommodative convergence has been shown to have no effect on nystagmus, hence spherical manipulation of spectacle prescriptions does not improve nystagmus.