Effect of Neuromuscular Blockade on the Oculomotor by Not Squinting Child
Condition: Strabismus
MeSH terms: Strabismus
Study type: Observational

Summary: 
      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.
    


Intervention name(s): Examination of the eye
Intervention type(s): Other
Intervention description(s): Before planed surgery, an ophthalmologist measures the patient's visual acuity and realise an oculomotor examination. Measurement the refraction and the axial length of the eye is performed. Photographs wakefulness are performed.
During surgery, participation in this study does not involve any change in the course of anesthesia and surgery.
Pictures of the eye will be performed under general anesthesia.
Timing photos will be dictated by the values of BIS and train-of-four (TOF). Photos will be conducted at different times, with the "top" given by the anesthetist under the following conditions:
Deep anesthesia: BIS <50 Deep anesthesia and muscle relaxation: BIS <50 and TOF 0/4
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients for whom surgery under general anesthesia with administration of curare is planned
      
Keywords: strabismus; surgical procedure; anesthesia; squint; child