Tonic Downward Movement of Eyes and Its Eccentric Positioning in Downgaze Under General Anaesthesia 

Abstract Objectives. To summarize abrupt eccentric eye positioning in downgaze following the downward movement of eyes encountered in patients undergoing ophthalmic surgeries under general anesthesia (GA) and analyze the relationship between the fluctuation in the depth of anesthesia (DOA) and eccentric eye positioning in downgaze. Subjects and Methods. Patients undergoing ophthalmic surgeries under GA without nondepolarizing muscle relaxant between January 2018-December 2019 in a tertiary-eye-care who witnessed a sudden tonic hypo-tropic movement of eyes were included in the retrospective, cross-sectional study. Results. A total of 8 patients out of 199 were enrolled in this study with an average age of 1.13±0.40years. All cases (3 pediatric cataracts, 4 strabismus, and 1 pseudophakia with posterior capsular opacification) were performed under GA with sevoflurane as an inducing agent. Downward movement was seen before the start of surgery in 4 cases and during surgery in 4 cases. Downward drift of eyes appeared tonic as the strong tug was felt in an extreme downward eccentric position. It was preceded by an eccentric upward drift of eyes following which sevoflurane concentration was increased to optimize DOA when this downward drift was encountered (mean minimal alveolar concentration/MAC 1.63±0.25). Downward movement was quick but return movement of eyes to the central position was gradual (mean 1.55±0.48minutes) when DOA was decreased (mean MAC 1.3±0.09).Conclusions. Tonic-downward movement of eyes or its eccentric positioning in downgaze is not an uncommon entity in children under GA without muscle-relaxant and fluctuations in DOA should be avoided to circumvent inadvertent complications during ocular surgery.