Modified dynamic visual acuity tests after acoustic neuroma resection.

CONCLUSION

These data suggest that visual acuity during quiet sitting is dynamic, requiring full body interaction of vestibulo-ocular and postural responses. These findings may have practical implications for seating design and design of tasks requiring good visual acuity while seated.

OBJECTIVES

Looking at something during quiet sitting is usually assumed to be a static activity. We tested the idea that visual acuity during quiet sitting is dynamic, requiring integration of whole body responses as well as intact vestibulo-ocular reflexes.

MATERIALS AND

METHODS

Normal subjects and patients scheduled for acoustic neuroma resection were tested preoperatively. Patients were then tested during the four in-patient postoperative days. Testing was done while seated, with or without head and back support, while reading numbers from slides on a laptop computer at eye level, in font sizes from 20 pt to 12 pt. The dependent measure was percent correct per font size.

RESULTS

In both groups scores while sitting unsupported were significantly higher than with full support or only back support. In patients, scores were significantly decreased on postoperative day 1 and gradually increased toward normal but maintained the pattern of better scores when sitting unsupported than with head or back support.