Denis Pelli^1,2, Emma Martindale³, Najib Majaj¹, Marialuisa Martelli², Sarah Waugh³; ¹New York University, ²University of Rome (Sapienza), ³University of Huddersfield

Waugh et al. (2018) reported the foveal crowding and acuity of 201 students, ages 3 to 11, in a primary school in Cambridge, UK. Crowding distance dropped threefold from age 3 to 8. More recently, in a primary school in Huddersfield UK, we tested 70 students, age 5 to 10, in fovea and periphery (0 and ±5 deg on the horizontal meridian). Over this age range, we replicate our 2018 foveal result, and discover a similar 3-fold drop in peripheral crowding, but 2 years later, from age 5 to 10. Note that the duration of the Sloan-letter triplet used to measure these thresholds was unlimited in the fovea, and only 200 ms in the periphery. We don’t know how much, if any, of the difference in results is due to the difference in stimulus duration. If the periphery’s two-year developmental delay remains with brief presentation in both places, then this represents a factor of three violation of the Bouma law, that crowding distance is linearly related to eccentricity.

Acknowledgements: URN020-01 from University of Huddersfield to Waugh.