Voluntary flutter (“nystagmus”)
Voluntary flutter, which is sometimes misdiagnosed as nystagmus, is characterized by irregular, brief bursts of rapid-frequency and low-amplitude eye movements with no slow phase (see Chapter 9).
Patients may report an inability to move the eyes horizontally or vertically. Such claimed gaze palsies may be overcome by a variety of maneuvers or tests, such as including those in oculocephalic reflex (doll’s head phenomenon), OKN drum, mirror tracking, and inner ear caloric stimulation.
Spasm of the near reflex
Spasm of the near reflex is characterized by episodes of intermittent convergence, increased accommodation, and miosis. Patients generally report diplopia and, at times, micropsia. The degree of convergence is variable, ranging from a large esotropia to only 1 eye turning in. This syndrome may be mistaken for unilateral or bilateral cranial nerve (CN) VI palsies, divergence insufficiency, horizontal gaze paresis, or ocular myasthenia gravis. Variability of the eye movements, miosis with convergent eye movements, and lack of other neuro-ophthalmic abnormalities are clues that can help the examiner reach the correct diagnosis. Further, when ductions are examined with 1 eye occluded or with oculocephalic testing, both eyes demonstrate full abduction, and the miosis observed with the eyes in an esotropic position immediately resolves. Although spasm of the near reflex is almost always observed in patients with nonorganic disturbances, it has also been associated with Arnold-Chiari type I malformation, posterior fossa tumors, pituitary tumors, and head trauma.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.