Three types of blink reflex evoked by supraorbital nerve, light flash and corneal stimulations

Three types of blink reflex were evoked by 1) supraorbital nerve stimulation, 2) light flash stimulation and 3) corneal touch. The blink reflex response was recorded simultaneously for both eyes by electromyography of the orbicularis oculi muscles of the lower eyelid. After supraorbital nerve stimulation, ipsilateral early response (R1) and bilateral late responses (R2) were demonstrated. The light flash stimulation evoked the photic early and late responses. The latency times of the R1, R2 and the photic early responses were determined in 22 normal subjects. The corneal touch was exactly timed using a new device and the latency time of the corneal blink reflex was determined. The latency of the ipsilateral corneal blink reflex was significantly shorter than that of the contralateral reflex. The blink reflexes by supraorbital nerve stimulation and light flash were studied concurrently in 7 patients with neurological disorders of vascular origin. The photic reflex was disturbed by bilateral occipital lobe lesions and also by affection of the rostral midbrain. The reflexes were not affected by lesions in the medial longitudinal fasciculus but were disturbed by widespread brainstem lesions of Foville syndrome. Clinical significance of a combined use of the supraorbital nerve and light flash stimulation was emphasized.