Succinyldicholine-induced return of the eyes to the basic deviation: a motion picture study

Area of Science:

• Ophthalmology
• Neuroscience
• Muscle Physiology

Background:

• The basic ocular position is crucial for binocular vision.
• Understanding the muscular control of eye position is essential for diagnosing and treating strabismus.

Purpose of the Study:

• To investigate the effect of succinyldicholine on the resting position of the eyes in anesthetized subjects.
• To explore the role of specific muscle fibers in determining the basic ocular position and their potential link to strabismus.

Main Methods:

• Administered succinyldicholine (2 mg/kg body weight) to 20 anesthetized subjects.
• Recorded eye position using motion pictures in both conscious and succinyldicholine-induced unconscious states.
• Measured the inter-eye distance to assess changes in ocular alignment.

Main Results:

• Succinyldicholine administration returned the eyes to the same basic horizontal position observed in the conscious state.
• The measured distance between the eyes showed high agreement (99 +/- 10%) between conscious and succinyldicholine-stimulated unconscious states.
• Previous research indicates succinyldicholine selectively causes sustained contraction of 'en grappe' muscle fibers.

Conclusions:

• 'En grappe' muscle fibers are implicated as determinants of basic ocular position.
• These muscle fibers are suggested to be a potential cause of strabismus.
• The findings provide insights into the neuromuscular control of eye alignment.