The effect of Retinitis Pigmentosa on activities of daily living

The majority of previous research investigating the impact of low vision on the completion of activities of daily living (ADLs) have examined visual impairment as a whole. The aim of this thesis was to provide a comprehensive overview of ADLs to determine what the most difficult areas are for people with Retinitis Pigmentosa (RP), a particular type of visual impairment. This research was achieved through both self-report questionnaire and objective analysis of human movement. 681 participants (570 with RP) were examined throughout this research. Identified through self-report, at the objective level, the most difficult ADLs amongst those with RP was mobility. In particular, at the goal level, this was identified as mobility outdoors (experimental chapter 1). Further, at the task level, orientation and walking around safely without bumping into things and tripping over or stepping off something were identified as most difficult (experimental chapter 2). Those who support people with RP perceived most of the ADLs significantly more difficult to complete (for those with RP), with greatest difference in perceptions between two groups being practical tasks. When assessing balance through measuring postural control (experimental chapter 3), those with RP showed similar postural control to those with normal vision when standing on a firm surface, regardless of the vision condition (eyes open or eyes closed). However, when standing on a foam surface with eyes open, the reduction in postural control among people with RP, compared to those with normal vision, highlighted the added importance of the somatosensory information to maintaining standing balance for those with RP. However, it was only apparent when the somatosensory system was disturbed. The examination of gait among people with RP (experimental chapter 4) demonstrated that those who used a mobility cane adopted a cautious walking behaviour in both level walking and obstacle crossing tasks. Such cautious behaviour was not evident for people with RP who did not use a cane, or for the normally sighted individuals. This thesis is the first to provide a comprehensive overview of self-report difficulties among those with RP. Findings also demonstrate the importance of maintaining adequate foot (somatosensory) and eye (vision) health for those with RP to regulate balance control. The additional mobility training for those with RP who use a cane is necessary for their walking gait. Furthermore, the support from the carers should reflect the needs of those with RP, which helps them with their independence in completing ADLs rather than overprotecting them.