Surgery for DVD: New Approaches
The oblique extraocular muscles appear to play a greater role than previously thought in dissociated vertical deviation (DVD). Scleral search coil recordings show that the vertical vergence component of DVD, because of the accompanying torsional changes, receives significant contribution from the oblique extraocular muscles. Based on these findings, new surgical approaches for DVD have been attempted, with the purpose of decreasing the vertical action of the oblique muscles. Recession and anterior transposition of all the oblique muscles has given an excellent result in some patients but a poor result in others, with correction averaging about half of the amplitude of the DVD. Large weakening procedures of all the oblique muscles, without anterior transposition, have not been helpful, not correcting more than 40% of the DVD in any case. Bilateral weakening of all four elevators has decreased the amplitude of DVD by 50 to 70%, but in two of three cases yielded objectionable retraction of both upper lids. The best surgical approach to DVD is yet to be determined and may depend upon specific assessment of the torsional and vertical components of the particular patient's DVD response.