Ocular torsion reveals the mechanisms of cyclovertical strabismus: the Weisenfeld lecture.

In the mid 1970s, during my ophthalmology training at Johns Hopkins, the mechanisms involved in the common horizontal misalignments of the eyes (horizontal strabismus) were reasonably well understood. At least the muscles involved were known. But even the common forms of cyclovertical strabismus were poorly understood: overacting /underacting oblique muscles, “A” and “V” patterns, dissociated vertical deviation, and congenital superior oblique paresis. Over the course of my career, the key to understanding the mechanisms involved in these forms of cyclovertical strabismus has been ocular torsion. This is a chronologic story of how I came to appreciate ocular torsion, learned how to measure it, and with a succession of colleagues have been able to use the torsional positions and torsional movements of the eyes to gain useful insight into the mechanisms involved in these forms of cyclovertical strabismus. Some of the “truths” that I believe we have discovered will seem very speculative to many— almost “leaps of faith.” As we continue to seek further evidence for the theories presented here, I frequently recall the “three stages of truth” attributed to the 19th-century philosopher Arthur Schopenhauer: “All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. And third, it is accepted as being selfevident.” My hope is that there will prove to be something new and valuable in what I have to say, valuable enough to withstand the test of time.