INTRODUCTION: Blepharospasm is a focal dystonia characterized by involuntary 
cocontraction of the eyelid protractors, causing spasmodic closure of the 
eyelids. Apraxia of eyelid opening is caused by an inability to initiate lid 
opening without paralytic abnormality. Some studies suggest that patients with 
either pure blepharospasm or blepharospasm associated with apraxia of eyelid 
opening are more prone to developing Parkinson's disease.
METHODS: In our study, 123I-FP-CIT (DAT) SPECT was performed in 24 patients with 
either pure blepharospasm or blepharospasm associated with apraxia of eyelid 
opening and no signs of parkinsonism to identify dopaminergic dysfunction.
RESULTS: DAT-SPECT was abnormal in 11 (46%) cases (five patients with isolated 
blepharospasm and six patients with blepharospasm associated with apraxia of 
eyelid opening) whose mean disease duration was 11 years.
CONCLUSION: Our study revealed presynaptic dopaminergic dysfunction, as 
determined by 123I-FP-CIT or DAT-SPECT, in nearly half of our blepharospasm 
patients (with or without apraxia of eyelid opening). Thus, the presence of 
blepharospasm might be an early sign of a parkinsonian syndrome.