Strabismus is a common condition (4-6% of the population) . The screening and treatment is a public health issue. Indeed, beyond the disfigurement, this disease is very supplier of amblyopia which is definitive if it is not detected and treated early (before 6 years old).
Initial treatment of strabismus is medical with orthoptic reeducation through penalization of the better eye in case of amblyopia or wearing optical correction in case of associated refractive disorder.
The second step is the treatment of strabismus is the surgery, when medical treatment has not resulted in a recovery of the visual axes. The principle of surgery is to weaken or strengthen one or more extraocular muscles of one (or two) eye to correct the eyes squint deviation. The main difficulty of surgical treatment is to assess the amount of strengthening or weakening muscles to do in order to obtain the best result and for a long time.
The investigators know that the postmortem anatomical position of the eyes is generally a slight elevation and divergence, but is inferior to the angle of divergence of the orbital axes. Curare and similar products which inhibit the nervous transmission at the neuromuscular junction, can be used to reproduce this situation in normal subjects.
The sign of general anesthesia is then to evaluate the angle of strabismus when the patient is under deep general anesthesia and with a complete muscle relaxation, obtained only when curarised it. If one or both eyes are recovering under general anesthesia, strabismus is mainly due to dynamic changes and surgery limiting muscle play (wire operation) and sometimes one eye is justified. A combination of both is possible (down + wireless), guided by the importance of the sign of general anesthesia on two prominent eyes or one eye. This sign of general anesthesia is however less known and most poorly quantified in healthy subjects. Yet it seems very important to determine what is deviation in normal subjects after neuromuscular blockade, as his eye movement is also subject to mechanical factors and spastic. This would indicate whether the state of rectitude (no strabismus) is the result of a deviation at complete rest (appearing under general anesthesia) and corrected by spastic elements wakefulness or, in another case this righteousness is already present in the state of general anesthesia (due to static factors) and slightly modified by enlightenment.
