['Automated perimetry, a psychophysical test, requires meticulous cooperation of the tested patient. Immigrant populations who do not speak the local language may have poorer performance. This study evaluates this effect.', 'The study was conducted in Israel where the dominant language is Hebrew. A total of 49 non-Hebrew speaking patients comprised the study group. The controls numbered 173 matched for age and gender. The examinations were conducted within the same 2 month period and by the same group of technicians. The groups were compared for clinical reliability score (RS), percent of fixation loss and a visual field damage score (VFDS). The RS and VFDS increased with poorer reliability or increasing damage. Hebrew speakers were uniformly instructed by the perimetry technician. Non-Hebrew speakers were instructed by technicians (N=34), or non professionals (accompanying person) N=15.', 'The mean age of the entire group was 69.7 +/- 13.1 years. The mean age of the study group was 67.1 +/- 18.0 years. The patients in the study group spoke seven different foreign languages. The reliability scores, percent fixation loss and VF damage scores did not differ significantly between the Hebrew and non-Hebrew speaking group. The subgroup of non-Hebrew speakers instructed by nonprofessionals had significantly poorer indices of reliability and higher VF damage scores.'] Does [ Language of instruction and the effect on visual field result ]?