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PURPOSE/METHODS: Bilateral visual field defects resembling an hourglass could be produced by bilateral lateral geniculate lesions. We recently encountered such deficits in a 37-year-old woman after an episode of central pontine myelinolysis. RESULTS/CONCLUSIONS: Automated static perimetry demonstrated the congruous visual field defects to involve both halves of the visual field. They were confirmed with kinetic perimetry, and they remained stable for four years. Magnetic resonance imaging demonstrated enhancing lesions characteristic of myelinolysis in each lateral geniculate.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ajo.2006.02.040 Byline: Sean P. Donahue Abstract: Previous studies evaluating the effect of anisometropia on amblyopia development have been biased because subject selection occurred as a result of decreased acuity. Photoscreening identifies anisometropic children in a manner that is not biased by acuity, and allows an opportunity to evaluate how patient age influences the prevalence and depth of amblyopia. Author Affiliation: Departments of Ophthalmology, Pediatrics, and Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee Article History: Accepted 24 February 2006 Article Note: (footnote) Supported in part by the Challenge Grant to Vanderbilt Department of Ophthalmology from Research to Prevent Blindness, Lions' Club International Foundation, Tennessee Lions' Charities. Based on a thesis prepared in partial fulfillment of the requirements for membership in the American Ophthalmological Society.

Reviewed by Sean P. Donahue, MD PhD Nashville, TN -- Knowledge of skew deviations and their management has changed dramatically in recent years. Skew deviations occur more commonly than previously [...]

Background: Sensorimotor and orbital anatomical mechanisms have been invoked to explain primary oblique muscle overaction. Method: Review of primitive visuo-vestibular reflexes and neuroanatomical pathways corresponding to vestibulo-ocular reflexes, and correlation with known clinical abnormalities in patients with primary oblique muscle overaction. Results: Bilateral superior oblique muscle overaction, which corresponds to a backward pitch in lateral-eyed animals, can occur when structural lesions involving the brainstem or cerebellum increase central otolithic input to the extraocular muscle subnuclei that modulate downward extraocular muscle tonus. Bilateral inferior oblique overaction, which corresponds to a forward pitch in lateral-eyed animals, may result from visual disinhibition of central vestibular pathways to the extraocular muscle subnuclei that modulate upward extraocular muscle tonus. Conclusions: Primary oblique muscle overaction recapitulates the torsional eye movements that occur in lateral-eyed animals during body movements or directional luminance shifts in the pitch plane. These primitive ocular motor reflexes become manifest in humans when early-onset strabismus or structural lesions within the posterior fossa alter central vestibular tone in the pitch plane. Arch Ophthalmol. 2001;119:1307-1314