Records of 106 patients, who had undergone weakening surgery on only one eye with an inferior oblique overaction, were reviewed. A normally acting second inferioroblique developed significant overaction after unilateral weakening in about one third of the cases. When even the slightest overaction was present at the time of surgery on the first, unilateral weakening was followed by a worsening of the other in slightly more than two thirds of the cases. The interval was no more than six months for the majority of patients and as little as two months in about half. Of 14 patients with only divergent or vertical misalignments, six developed increasing overaction of the unoperated muscle after unilateral surgery.
Raab EL, Costenbader FD. Unilateral Surgery for Inferior Oblique Overaction. Arch Ophthalmol. 1973;90(3):180–182. doi:10.1001/archopht.1973.01000050182002