Corneal sensitivity during and outside attacks of cluster headache.

Corneal sensitivity has been studied in cluster headache (n = 38) and controls (n = 16). The patients were studied either during remission (n = 20), interparoxysmally in a bout (n = 17), or during attacks (spontaneously occurring attacks (n = 5) and nitroglycerin-provoked attacks (n = 6). For the measurements, a Cochet-Bonnet esthesiometer was utilized. This esthesiometer has a 6 cm long, adjustable nylon monofilament, which can be reduced in length by 0.5 cm at a time, the length of the filament determining the pressure exerted onto the corneal surface. All controls sensed the pressure at 6.0 cm filament length. In 5 cluster headache patients (remission, n = 4; cluster period, n = 1) a slight reduction in corneal sensitivity was found. No statistical difference was, however, found between any of the groups tested, and there was no asymmetry as far as averages were concerned.