Science

Colour blind cricketers and snowballs

BMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6970.1684 (Published 24 December 1994) Cite this as: BMJ 1994;309:1684
  1. Nicholas Goddard, consultant orthopaedic surgeona,
  2. Dominic Coull, medical studenta
  1. a Royal Free Hospital and School of Medicine, London NW3 2QG
  1. Correspondence to: Mr Goddard.

    Abstract

    Objective: To determine whether colour blindness affects batting in professional cricketers.

    Design: Comparison of batting averages of colour blind cricketers and those with normal vision.

    Setting: Players on 18 first class county cricket teams. Subjects—280 of 306 players were tested.

    Main outcome measures: Results of Isihara colour blindness tests.

    Results: Batting average for the colour blind group (12 players) was slightly lower than for players with normal vision (20.88 v 26.31). There was no difference in the number of batsmen and bowlers affected. Batting averages before and after the introduction of the white ball into Sunday League cricket did not differ significantly.

    Conclusions: That batting performance is not significantly impaired by colour blindness suggests that to some extent these players are self selected. Routine testing of cricketers for colour blindness is not recommended.

    Introduction

    This study was motivated by the senior author's redgreen colour blindness, coupled with his singular lack of ability to hit a (red) cricket ball moving at speed. As he is able to hit a white rounders ball or baseball or a black squash ball with some degree of accuracy and reliability, it must be assumed that colour blindness has some role. If red-green colour blindness alone caused this inability a similar visual handicap in professional cricketers could adversely affect batting performances, especially with a red cricket ball—travelling at 80 mph (130 km/hour) or more—rising off a lush green wicket.

    The study aimed to determine the prevalence of redgreen colour blindness in a group of professional cricketers. Four questions were to be answered:

    1. Are cricketers less likely to be colour blind than men in the general population?

    2. Are batsmen less likely to be colour blind than bowlers?

    3. Does colour blindness affect batting ability?

    4. Would introducing a white ball into Sunday League cricket make any difference to colour blind players?

    Methods

    During the course of the 1993 cricket season the playing staff of every first class county side (18 teams) were tested for red-green colour blindness by using standard Ishihara test charts. No additional tests of visual acuity or depth of vision were carried out. When appropriate, players wore their normal contact lenses or spectacles. We were able to test 280 cricketers of the 306 listed, which represents 92% of the playing population.

    To assess the influence of the white ball we compared the batting averages of colour blind players in the AXA Equity and Law Sunday League in the two seasons before and after its introduction.

    Results

    Eight per cent of men in the general population are red-green colour blind.1 Of the 280 players we tested, 12 (4%) had red-green colour blindness. This difference is statistically significant (z=3.053; P=0.0023).

    The players affected reflected the composition of normal cricket team (and 12th man)—five were predominantly batsmen, two were all-rounders, one was a wicket keeper, and four were predominantly bowlers.

    Information obtained from Playfair2 allowed the batting performances of affected players to be compared with those of the entire cricketing cohort (306 players). The average batting performance for all cricketers was 25.631 (SD=14.35) for the season. The batting average for the colour blind group was slightly below this at 25.51 (11.43). This difference was not statistically significant.

    The mean batting averages of the colour blind players over the two seasons since the introduction of the white ball into Sunday League cricket (21.64, SD=14.8) and the previous two seasons (18.94, SD=11.82) seems to show a slight improvement in the batting figures, but this difference is not statistically significant. It is not appropriate to compare differences in batting averages between the one day and the four day games.

    Discussion

    Our figures show that the incidence of red-green colour blindness in professional cricketers is approximately half of that in the normal male population. There seems to be no difference between the numbers of batsmen and bowlers affected. Batting performance is not significantly impaired, suggesting that to some extent these players are self selected and cope with their colour blindness. Indeed, one former international opening batsman is sufficiently colour blind so as to have extreme difficulty distinguishing the colour of snooker balls (G G Arnold, personal communication).

    We do not recommend routinely assessing players for colour blindness. The white ball in the one day game seems to make little difference to batting performance.

    We thank all the county coaches, captains, and players who cooperated so kindly and patiently during the course of our research, and Mr Richard Lockwood for providing the statistics for the AXA Equity and Law Sunday League.

    References

    1. 1.
    2. 2.
    View Abstract

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