Purpose: To investigate the effect of periocular warming on accommodation amplitude and near vision after prolonged near work in visual display terminal (VDT) workers in an office setting.
Design: Prospective interventional observational case series.
Participants: Ten healthy Japanese male volunteers (mean age, 39.3+/-2 years [range, 36-43]) with a best distance corrected visual acuity (VA) of >20/20 who performed near work for 7 hours were included in the study.
Main outcome measures: The differences of subjective and objective accommodations, near acuity, and pupil diameters were compared and studied in 2 experimental settings with and without periocular warming.
Methods: Two experiments were performed on each subject on 2 different days. In one experiment, the subjects wore an eye mask and closed their eyelids for 10 minutes after 7 hours of VDT work (lid closure [LC] group). In the other experiment, the subjects applied warming sheets (WSs) to their eyelids and the periocular region and wore masks for 10 minutes again after 7 hours of VDT work (WS group). Visual display terminal work was performed under the same settings on both days. Subjective and objective accommodations, near vision, and pupil diameters were measured immediately before and immediately after the resting or warming procedure and again 90 minutes after the resting or warming procedures.
Results: Fifty percent of eyes had an increase in the accommodation amplitude of at least 0.5 diopters immediately after application of the WSs. Forty percent of eyes still maintained the accommodation amplitude level at 90 minutes. The mean near logarithm of the minimum angle of resolution VA immediately after application of WSs and at 90 minutes significantly improved relative to the near acuity values after simple eyelid closure.
Conclusion: Periocular warming was found to be associated with increases in subjective and objective accommodations, with a concomitant improvement in near VA. Periocular warming with disposable WSs is a simple and effective method of increasing near work-related ergonomy.