We review ocular motor cranial nerve palsies in childhood and highlight many of the features that differentiate these from their occurrence in adulthood. The clinical characteristics of cranial nerve palsies in childhood are affected by the child's impressive ability to repair and regenerate after injury. Thus, aberrant regeneration is very common after congenital III palsy; Duane syndrome, the result of early repair after congenital VI palsy, is invariably associated with retraction of the globe in adduction related to the innervation of the lateral rectus by the III nerve causing cocontraction in adduction. Clinical features that may be of concern in adulthood may not be relevant in childhood; whereas the presence of mydriasis in III palsy suggests a compressive aetiology in adults, this is not the case in children. However, the frequency of associated CNS abnormalities in III palsy and the risk of tumour in VI palsy can be indications for early neuroimaging depending on presenting features elicited through a careful history and clinical examination. The latter should include the neighbouring cranial nerves. We discuss the impact of our evolving knowledge of congenital cranial dysinnervation syndromes on this field.

Snowflake degeneration is a slow progressive opacification of polymethyl methacrylate (PMMA) intraocular lenses (IOLs). This late postoperative complication can occur a decade or later after implantation. The deposits are composed of IOL materials that tend to aggregate centrally. There is a relative paucity of the literature on snowflake degeneration of IOLs. Symptoms can range from mild visual disturbance to significant loss of visual acuity. In cases of opacification after IOL implantation, the different diagnosis should include snowflake degeneration to prevent surgical intervention such as lens exchange or explantation unless clinically warranted. We report a case of late optical opacification of a PMMA IOL, the clinical diagnosis and treatment that increased best corrected vision.