Human pupillary light reflex during and after two-fold Valsalva maneuver.

The influence of the Valsalva maneuver on the pupillary light reflex and on the parameters of human pupillogram were studied in 9 normal volunteers (mean age 21.0 years). The consensual pupillary reactions to light were recorded using a infrared-reflecting pupillograph; pupillogram records were processed off-line by a computer system. Latency time increased during the Valsalva maneuver and normalized in the first minute after its end. No significant changes were found in constriction time. Half-redilatation time showed the opposite dynamics of latency time. The amplitude diminished during Valsalva maneuver and in the first minute after it. These results suggest a possible alteration of the autonomic nervous regulation during Valsalva maneuver and especially some changes in parasympathetic outflow to human iris sphincter. The possible effect of prevailing parasympathetic or sympathetic activity on pupillometry parameters during some phases of the Valsalva maneuver and after its end is discussed.