Spasm of the Near Reflex
- Diplopia and esotropia caused by inappropriate activation of convergence, miosis, and accommodation (“synkinetic near triad”)
- Usually episodic but may be sustained
- Common causes: anxiety or malingering
- Uncommon cause: idiopathic
- Often triggers major caregiver concern that a dire neurologic condition has developed
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Core clinical features
- Diplopia or blurred vision for distant objects
- Comitant esotropia for distance fixation
- Eyes aligned for near fixation
- Episodic convergence movements
- Episodic miosis (may be difficult to see)
- Episodic accommodation (only in patients under age 50)
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Possible accompanying clinical features
- Volitional flutter eye movements
- Blepharospasm
- Staggering gait
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Tip: these manifestations are difficult to sustain for long periods
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Imaging features
- No abnormalities
- Decompensated esophoria
- Accommodative esotropia
- Esotropia of high myopia
- Sixth nerve palsy
- Thalamic infarct, hemorrhage, tumor (“thalamic esotropia,” “pseudoabducens palsy”), but manifestations are never intermittent
- Pontine dysfunction, but in that condition, convergence is a substitution for markedly impaired horizontal gaze
- Ocular dysmetria
- Ocular flutter/opsoclonus
- Nystagmus
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Tip: look for the characteristic undulating horizontal gaze movements evoked by intrusion of convergence on conjugate horizontal gaze
- Try to detect miosis timed with intrusion of convergence movements
- In young patients, see if retinoscopy will disclose a myopic shift of accommodation (“pseudomyopia”) timed with convergence movements
- Test ocular ductions by covering one eye at a time, expecting to evoke horizontal movements of normal amplitude
- Expect accompanying volitional flutter and/or blepharospasm
- Monocular occlusion or cycloplegia may relieve the spasm, but these approaches are often not effective
- Psychotherapy or sedative medication may help
- Condition may resolve spontaneously
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Trap: eye muscle surgery (bimedial rectus recessions) may lead to exotropia