The importance of cyclotorsional changes in refractive surgery.

PURPOSE To provide evidence of the importance of a precise record of torsional alterations in all patients about to undergo refractive surgery and particularly in patients with latent strabismus that may become decompensated due to the dissociation phenomenon produced during different surgical procedures that result in fixation loss. METHODS Using 3D-VOG video-oculography, the authors analyzed the horizontal, vertical, and torsional movements of each eye after inducing fixation loss in one and both eyes in a patient with well-compensated dissociated vertical deviation (DVD). As the dissociated techniques, Posner maneuver and the placing of Bagolini filters with increasing densities by means of the Bielschowsky phenomenon, both pathognomonic of DVD. RESULTS The authors observed not only horizontal and vertical alterations, but also cyclotorsional alterations which may even exceed 15 degrees depending on the resulting dissociation component. CONCLUSIONS In view of the obtained results, the authors consider it important to conduct a meticulous study of ocular motility in all patients about to undergo refractive surgery, especially in the case of high astigmatism to rule out possible latent strabismus that may condition cyclotorsional alterations important in refractive surgery.