Visual Function of Visually Impaired Paralympic Skiers

Abstract

Purpose : Visually Impaired (VI) Paralympic skiers are classified into groups for competition based on their level of impairment. The current classification system considers visual acuity (VA) and visual field size in the better eye only. No other measures of visual function are considered. The purpose of this study was to examine a wide range of visual functions in elite VI skiers, to determine the range of visual impairment in this population and how the measures of visual function are related in individuals with visual impairment.

Methods : 61 skiers participated in this research, including 29 Alpine (downhill) skiers (age 12-69 years) and 32 Nordic (cross-country) skiers (age 12-48 years). 38 skiers were male, 23 were female. Static VA (ETDRS and Berkeley Rudimentary Vision Test charts), contrast sensitivity (CS; Pelli-Robson chart), dynamic VA and low contrast VA (moV&, V&mp Vision Suite), colour vision (large D-15) and glare sensitivity and glare recovery time (glare source + MARS charts) were measured. All tests were completed binocularly with the exception of glare sensitivity and recovery, which were completed monocularly. Data were not normally distributed, therefore correlations between visual function parameters were examined using Spearman’s rho. P-values were adjusted using Holm’s method to control for multiple comparisons.

Results : Static VA was quantifiable in 55 athletes (1.54 logMAR ± 0.72, range 0.14 logMAR to no light perception). CS (n=50) was 0.64 logCS ± 0.50 (range 0.00-1.55 logCS). Significant correlations (p<0.01) were found between a number of visual function parameters, including static and low contrast VA (r_s=0.863), static and dynamic VA (r_s=0.773), static VA and CS (r_s=-0.749), low contrast and dynamic VA (r_s=0.899), CS and low contrast VA (r_s=-0.641), CS and dynamic VA (r_s=-0.565), and glare sensitivity and glare recovery (r_s=0.477).

Conclusions : A wide range of visual functions can be measured in VI skiers. Different measures of visual acuity (static, dynamic and low contrast) were highly correlated. Contrast sensitivity also correlated with measures of acuity. It is possible that measurement of some of the visual functions examined in this study could improve the current VI skiing classification system. Future research will focus on determining the relationship between these visual functions and skiing performance.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.