The resilience of natural interceptive actions to refractive blur

David L. Mann, Bruce Abernethy, Damian Farrow

The impact of refractive visual blur on interceptive skill was examined for a series of highly-demanding striking tasks. Ten skilled cricket batsmen were required to intercept balls projected by either a ball projection-machine (medium-pace only) or cricket bowlers (two velocities; medium-pace and fast-pace) under each of four systematically varied visual conditions. Contact lenses were fitted to simulate increments in refractive blur (habitual, +1.00, +2.00, +3.00D), with changes in interceptive performance evaluated on three concurrent measures of performance relevant to cricket batting (quality of bat-ball contact, forcefulness of bat-swing, and likelihood of dismissal). For the projection-machine condition, results replicate those reported previously (Mann, Ho, De Souza, Watson, & Taylor, 2007) with blur needing to reach +3.00D before any significant decreases in performance were evident, a finding further replicated when facing bowlers of comparable velocity. The influence of blur on interception was found to interact with ball-velocity, with the increased temporal demands of fast-paced trials resulting in decreased performance becoming evident at a lower level of blur (+2.00D). The findings demonstrate that even when presented with a situation replicating highly-demanding performance conditions, substantial degradation of visual clarity is possible before acuity is a limiting factor for interceptive performance.