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Published on: August 1, 2018
Ocular motor behavior in macaques with surgical exotropia
John R Economides1, Daniel L Adams, Cristina M Jocson
1Beckman Vision Center, University of California, San Francisco, CA 94143-0730, USA.
Journal of Neurophysiology
|October 12, 2007
Summary
Researchers created a new animal model for human exotropia by surgically altering eye muscles in infant macaques. This model mimics key features of human strabismus, aiding future studies on visual suppression.
Area of Science:
- Ophthalmology
- Neuroscience
- Animal Models
Background:
- Exotropia is a common form of strabismus characterized by outward turning of the eye.
- Animal models are crucial for understanding the complex mechanisms underlying strabismus and developing effective treatments.
Purpose of the Study:
- To establish a reliable animal model of human exotropia using macaques.
- To investigate the functional and anatomical consequences of medial rectus tenotomy in infant macaques.
Main Methods:
- Medial recti tenotomy was performed on two infant macaques.
- Post-surgery, eye movements, ocular alignment, smooth pursuit, fixation preference, and gaze stability were assessed using video eye trackers.
- Muscle re-attachment and resulting ocular alignment were monitored.
Main Results:
- Spontaneous re-attachment of the medial rectus muscle led to partial adduction recovery but resulted in significant, comitant exotropia.
- Exotropia magnitude was unaffected by eye covering; no dissociated vertical deviation or significant "A"/"V" patterns were observed.
- Smooth pursuit was more accurate nasally, and alternating fixation with accurate saccades was maintained. One macaque developed vertical pendular nystagmus.
Conclusions:
- Medial rectus tenotomy in macaques provides a valuable model for human alternating exotropia.
- This model will facilitate research into the cortical mechanisms of visual suppression in strabismus.
- The study highlights the utility of macaques in strabismus research, particularly for understanding visual processing in misalignment.
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