Unequal accommodative response in the two eyes when fixating an object binocularly. It may result from a disease (e.g. glaucoma, ophthalmoplegia, paralysis of the third nerve, unilateral cataract), uncorrected anisometropia, viewing a near object to the side, toxins affecting one eye more than the other, or trauma.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann