A QUANTITATIVE EXPERIMENTAL STUDY TO INVESTIGATE THE EFFECT OF SIMULATED TUNNEL VISION ON POSTURAL STABILITY IN THE HEALTHY POPULATION

Y.H. Wong¹, E. Drury¹

¹University of Leicester, Physiotherapy, Leicester, United Kingdom

Background: Tunnel vision is a visual impairment that restricts the peripheral visual field. Vision and postural stability are closely interlinked, and it contributes to maintaining the body in an upright posture. Tunnel vision mainly affects people with retinitis pigmentosa and glaucoma which can negatively impact the quality of life, such as reduced postural stability. Although lots of studies have explored how tunnel vision impacts navigation, no study has explored the influence of tunnel vision on postural stability.

Purpose: To use the Biodex Balance System to measure the postural stability of participants with and without simulated tunnel vision spectacles.

Methods: 15 healthy participants were recruited from the Physiotherapy course at the University of Leicester. Participants completed the postural stability test on the Biodex Balance System with and without simulated tunnel vision spectacles. Ethics was approved by the University’s ethics committees before data collection. A crossover design was used, and participants were randomised into two groups: with or without simulated tunnel vision spectacles. Three 20 seconds trials were completed for each intervention, with a 5-minute rest before redoing the test for the other intervention. This study provided a mean overall stability index. Boxplot and histogram were used to display the distribution of the data. Paired t-test and p-value were used to analyse participants’ results on postural stability.

Results: Results showed that postural stability was negatively impacted by simulated tunnel vision. The mean overall stability index were 2.71 and 5.36 for without and with tunnel vision spectacles groups respectively. The standard deviation was 1.68 for the group without tunnel vision spectacles and 2.41 for the with tunnel vision spectacles group. Shapiro-Wilks test for the without tunnel vision spectacles group showed a significance of p=<0.001 and p=0.696 for the with tunnel vision spectacles group. The Wilcoxon signed ranks test resulted in Z=-2.795, illustrating findings to be significant.

Conclusions: Statistical analysis of the data indicated that postural stability was negatively influenced by simulated tunnel vision. Results obtained in this study were supported by existing studies exploring the influences between visual impairments and postural stability. Due to limited studies available for tunnel vision, this study highlights the importance of further research needed. The methodology of this study could be replicated for future studies with a larger sample size to explore how postural stability affects the tunnel vision clinical population.

Implications: Tunnel vision is a severe symptom mainly occurring in retinitis pigmentosa and glaucoma, which can happen at any age. While the visually impaired population are already more prone to falls, the addition of the ageing factor makes them at a higher risk of fall injuries. Future studies can incorporate current findings into the development of postural stability treatments, to compensate for the reduction of the visual system and therefore improve patients’ quality of life and mobility.

Funding acknowledgements: This research received no grant from any funding organisations in the public or not-for-profit sectors.

Keywords:
Tunnel vision
Postural stability
Biodex Balance System

Topics:
Disability & rehabilitation

Did this work require ethics approval? Yes

Institution: University of Leicester

Committee: Medicine and Biological Sciences Research Ethics Committee

Ethics number: 32519-yhw14-ls:medicine