Microfluctuations of steady-state accommodation and the cardiopulmonary system.

The relationship between variations in steady-state accommodation (microfluctuations) and rhythmic cycles in cardiopulmonary system was investigated. As previously reported, vascular pulse frequency was consistently correlated with the high frequency component of steady-state accommodation microfluctuations. In a new finding, respiration rate and an associated cycle in the instantaneous pulse rate also showed a correlation with a low frequency component of the accommodation power spectra. This apparent coherence between respiration frequency and an accommodation low frequency component was maintained during rapid breathing and was evident at the expected frequency during regulated breathing patterns. This association may reflect the direct influence of the autonomic nervous system upon the ciliary muscle or may be caused by the modulation of intraocular pulse by the autonomic nervous system.