Objective quantification of viewing behaviours during printed and electronic tasks in emmetropic and myopic ultra‐Orthodox Jewish men

Abstract

AbstractPurposeUltra‐Orthodox Jewish men are known to have a high prevalence of myopia, which may be due to intense near‐work from an early age. This study objectively assessed near‐viewing behaviours in ultra‐Orthodox and non‐ultra‐Orthodox men in Israel for different tasks.MethodsUltra‐Orthodox (n = 30) and non‐ultra‐Orthodox (n = 38) men aged 18–33 years participated. Autorefraction, visual acuity, height and Harmon distance were measured. An objective range‐finding sensor was mounted on their spectacles while they performed four 10‐min tasks in a randomised order: (1) reading printed material, (2) writing printed material, (3) passive electronic and (4) active electronic tasks. Near‐viewing distance and the number of viewing breaks were calculated for each task. Statistical analyses included Student t‐tests and the Mann–Whitney test between groups and repeated measures ANOVA or Friedman between tasks.ResultsFor all tasks combined, a significantly shorter viewing distance was observed for the ultra‐Orthodox group (36.2 ± 7.0 cm) than for the non‐ultra‐Orthodox group (39.6 ± 6.7 cm,p < 0.05). Viewing distances for the passive reading and electronic tasks were shorter for the ultra‐Orthodox group (36.9 ± 7.7 cm vs. 41.3 ± 8.1 cm,p < 0.03 and 39.0 ± 10.1 vs. 43.9 ± 9.3,p < 0.05, respectively). Viewing distances were significantly different between all four tasks, with writing having the closest distance. No correlation was found between working distance and spherical equivalent or Harmon distance. However, a significant correlation was found in the ultra‐Orthodox group between working distance and height for each task (p < 0.04,R < 0.42 for all). There was no difference in the number of viewing breaks between the groups.ConclusionWhen reading a book and viewing an iPad, ultra‐Orthodox men demonstrated a closer objective working distance than non‐ultra‐Orthodox men. This shorter viewing distance may contribute to the high prevalence and degree of myopia in this population.