INFLUENCES OF THE ACCOMMODATIVE STIMULUS AND AGING ON THE ACCOMMODATIVE MICROFLUCTUATIONS

The effects of the accommodative stimulus and age on the accommodative microfluctuations were investigated in human subjects. Accommodative responses were measured by using an infrared (IR) optometer, and accom modative microfluctuations were quantified by power spectrum analysis. Two frequency bands were determined: low frequency components (<0.5; Hz, LFC) and high frequency components (1.3 to 2.2 Hz, HFC). Among you nger subjects, the changes in the HFC in response to the accommodative stimuli differed between subjects, The activity of the HFC reached a peak in the center of the accommodation range, whereas the activity of the LFC was its maximum in the presence of darkness or blur in the ov er-accommodation range, Smaller changes in the magnitude of the HFC we re observed in older subjects. Although the LFC may be controlled neur ologically, the HFC seems to arise from mechanical and elastic propert ies of the lens, and may be modulated by other physiological rhythmic variations.