Effect of light on blinking in patients with idiopathic isolated blepharospasm.

OBJECTIVE: Melanopsin may be involved in the pathophysiology of photophobia in idiopathic isolated blepharospasm. We assessed the efficacy of blocking wavelengths of melanopsin absorption to reduce blinking in blepharospasm as a possible surrogate for photophobia. METHODS: Twenty-one participants (11 blepharospasm and 10 healthy controls) were studied. There were three sessions: (1) a baseline condition to measure the blink rate (BR) without intervention; (2) two conditions where the participants received intermittent light stimuli with high or low intensity without wearing study lenses; (3) four conditions in which the participants received intermittent light stimuli with high intensity while wearing one of four different lenses: tinted lenses with neutral gray or FL-41, or coated lenses that block 480-nm or 590-nm wavelength. The primary outcome measure was the BR. RESULTS: The blepharospasm group blinked more frequently than controls in dim room conditions. Patients reported greater photosensitivity compared to controls based on the questionnaire and exhibited a higher BR with intermittent light stimuli. The BR decreased for both groups when using 480-nm and 590-nm blocking lenses. In the patients, 480-nm and 590-nm blocking lenses reduced the mean BR by 9.6 blink/min and 10.3 blink/min, respectively, while in the control group, the mean BR decreased by 4.4 blink/min and 4.3 blink/min, respectively. CONCLUSIONS: Blepharospasm patients had increased BR with light stimuli which decreased with 590-nm and 480-nm blocking lenses. The 480-nm- and 590-nm- coated lenses might have therapeutic potential in treating photophobia although BR does not appear to be an optimal biomarker for photophobia.

Cerebral and spinal air embolism following percutaneous nephrolithotomy.

We present a case report of cerebral and spinal air embolism following percutaneous nephrolithotomy in a patient without evidence of intra-cardiac defects or prepulmonary A-V shunts. The position of the patient during the incidence determined the site of eventual lodgement of air emboli in the arterial circulation. We suspect that the time of onset of symptoms following the procedure may be the clue to the path followed by air emboli.

Substantia nigra lesions in viral encephalitis.

Post-encephalitic parkinsonism is a well-known entity, but involvement of the basal ganglia is rarely documented. We describe a 21-year-old man who developed parkinsonism following encephalitic illness presumed to be of viral origin with substantia nigra lesions evident on magnetic resonance imaging scan.