1. McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Province of Quebec, Canada
2. McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Province of Quebec, Canada 2School of Optometry, University of Waterloo, Ontario, Canada
3. Department of Psychology, University of York, York, United Kingdom
4. School of Optometry, University of Waterloo, Ontario, Canada