The effect of orientation and mobility training on vision and mobility performance in visually impaired adults

A number of studies have investigated various visual functions of visually impaired subjects and how their visual functions relate to the subjects' ability to travel in their environment. Most studies have shown that visual field and contrast sensitivity are the most important visual factors in determining how well visually impaired subjects travel in their environment. From the outcome of the studies, some aspects of vision are known to play important roles in mobility performance of visually impaired subjects. However, in all these studies, researchers have used visually impaired subjects with differing degrees of mobility skills. The mobility performance measured in previous studies may differ among subjects depending on the level of their mobility skills rather than differences in visual function. One of the main factors which may affect subjects' mobility skills is whether or not they have had orientation and mobility (OM it accounted for 20.4 percent and 31.2 percent of the variance in PPWS and error score respectively before training whilst accounting for 20.0 percent and 16.8 percent of the variance in PPWS and error score respectively after training. Stepwise multiple regression analysis of groups T and NT together showed that LCV A and inferior remaining visual field were best predictors of PPWS and error score respectively; PPWS began to deteriorate when LCVA was 6/150 or worse whilst error score began to decline when inferior remaining visual field was 45 degrees radius or less (between the field extent of 225 and 315 degrees). Conclusions. Mobility performance of visually impaired adults may be improved following O&M training, however, further research needs to be conducted to ascertain the level of improvement in performance over time. Visual field was shown to play a significant role in mobility performance of visually impaired adults regardless whether or not they have had O&M training, however, further research is required to ascertain the role of LCV A in walking efficiency. Tentative criteria for O&M training referral were recommended: LCVA 61150 or worse and/or inferior remaining binocular visual field of 45 degrees or less using the target IV 4 E. However, further research is needed to ascertain if these criteria are applicable to other visually impaired groups.