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The morphology of the afferent synapse in type I (HCI) and type II (HCII) saccular hair cells was compared in juvenile and very old C57BL/6NNia mice. Normal membrane specializations and normal synaptic body (SB) form and organization were found to continue well beyond the expected life span. Although SB were found less frequently in HCI than in HCII, they were as readily found in old saccules as in juveniles. The elongated rod was the most common form in HCI and the spheroid was the most common in HCII. Large clusters of SB (greater than 5), found in both juvenile and old saccules, were unique to HCI. SB in HCII were generally found singly. A range of forms, including hollow and striated dense bodies, also occurred in both juvenile and very old saccules. Singular or clustered SB were found free in the cytoplasm as well as engaged at the membrane. No SB were seen at sites other than nerve terminal appositions. In rare instances a SB was observed engaged at a site that appeared to be opposite an efferent fiber.

Background:The diagnosis of incomplete third nerve palsy can be clinically challenging because the aetiologies, as well as presentations, can be variable and subtle. The optometric clinician should be familiar with the association of third nerve palsy with compressive lesions, including the clinical presentations and management of these patients. Case report: We present a 68-year-old hypertensive male complaining of intermittent diplopia for the previous six months. Neurological examination revealed a mild deficit in adduction, reduced range of vertical motility and questionable ptosis, all limited to the OD. No pupillary involvement was noted. MRI revealed a cavernous sinus meningioma. The patient elected against surgery, choosing MRI every six months. Conclusion: Due to the subtle clinical presentation of incomplete pupil sparing third nerve palsy, this ophthalmoplegia may be easily overlooked. The associated aetiologies of palsy of cranial nerve three (CN3) carry increased risk of morbidity and mortality. Management should include evaluation for mass lesions and/or vascular aetiologies, regardless of pupillary involvement.Pupil sparing incomplete third nerve palsy secondary to a cavernous sinus meningioma: challenges in management

This study indicates that the optic nerve parameters as measured by the Heidelberg retinal tomograph II do not differ between migraine sufferers and age-matched control subjects.

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