Dissociated vertical deviation: an asymmetric condition treated with large bilateral superior rectus recession.

Bilateral superior rectus recessions were performed on 25 patients for dissociated vertical deviation (DVD). Large recessions (at least 10 mm from the original insertion) have proved effective and safe, although all patients were slightly undercorrected. There were no complications of ptosis, upper lid retraction, alterations of palpebral fissure width, failure of upgaze, oblique dysfunction or overcorrection. The DVD was always asymmetric, with the greater deviation in the non-dominant eye. Forty percent of the patients had a decompensated asymmetry manifested by unilateral hypertropia of at least 10 prism diopters in addition to the DVD. These patients require an asymmetrical amount of surgery. Two such patients required reoperation, not because of residual DVD, but because of failure to correct this hypertropia. Currently we do bilateral superior rectus recessions of greater than 10 mm OU for DVD, reserving unilateral surgery for the patient with such deep amblyopia that he will never fix with the operated eye. An eye with manifest hypertropia in addition to DVD requires at least five more millimeters (greater than 15 mm) than the fixating eye. Maximum amounts of recession have not yet been determined.