Idiopathic blepharospasm does not lead to a parkinsonian syndrome: resultsof a questionnaire-based follow-up study

It has been suggested that a lesion in the dopaminergic neurons of the subs tantia nigra pars compacta combined with eye irritation is involved in the pathophysiology of idiopathic blepharospasm. If so, these patients might be prone to develop Parkinson's disease or a parkinsonian syndrome. We theref ore conducted a validated questionnaire-based follow-up study to estimate ( a) the frequency of local eye disorders at onset and (b) frequency of devel opment of parkinsonian symptoms in blepharospasm patients. Ninety-nine pati ents previously diagnosed with idiopathic blepharospasm were sent a two-par t questionnaire to assess parkinsonian and other symptoms associated with t heir condition. The average period of follow-up was 12.7 years, ranging fro m 3 to 26 years, with an average age at onset of 53.5 years. Sixty-two pati ents reported other ocular symptoms prior to or at the onset of blepharospa sm, and therefore ocular disease may act as a trigger to produce blepharosp asm in those already predisposed. Only two patients had developed a score o n the parkinsonism rating scale indicating possible Parkinson's disease, bu t clinical examination confirmed this not to be the case. If a lesion in th e dopaminergic neurons is involved in blepharospasm, it would appear to be relatively minor (and non-progressive), since patients with idiopathic blep harospasm do not seem prone to develop parkinsonian symptoms.