Surgery for vertical muscle imbalances is now far beyond experimental stages. Once a definitive diagnosis has been established, the proper procedure to correct the defect is well delineated. Adherence to certain common-sense principles and the exercise of good surgical techniques will usually lead to a rewarding result.
An entirely different situation exists regarding the relatively newly described A-V syndromes. These qualify for inclusion in any discussion of vertical imbalances, since they not only manifest vertical incomitancy in the direct upward and downward gazes, but they usually have an accompanying vertical component which may or may not be a true defect. Surgery is still in an experimental stage, since the etiology of these syndromes is not established, and concepts of therapy vary.
There are no firmly established and proven surgical principles for the A-V syndromes. Some general statements will be made later.Principles of surgery for the "conventional" vertical
DUNLAP EA. Selection of Operative Procedures in Vertical Muscle Deviations. Arch Ophthalmol. 1960;64(2):167-174. doi:10.1001/archopht.1960.01840010169001