Sir,

Problems with left right discrimination can cause medical errors including investigation or treatment of the wrong eye, which may result in potentially serious consequences.1 The ability of doctors and medical students to correctly discriminate left and right has already been extensively explored2 and because of varying ability to discriminate effectively, numerous safety checks exist to prevent errors. Previous studies have also demonstrated differences in ability to discriminate based on educational level3 and sex.4 It has not been previously explored whether language preference has any bearing on left right discrimination. It seemed that patients that attended our clinics who could correctly lateralise were less frequent than the quoted rates of between 80.5 and 73.4%.4, 5 We decided to look at the ability of patients attending our outpatient department to discriminate left and right and look for differences between sexes and language used in the consultation, Welsh or English.

Patients attending outpatient ophthalmic clinics in South West Wales were asked to ‘look to their right’ as part of the routine slit-lamp examination and tallies of correct responses were taken, along with details of sex and language of consultation. The language used was based on that of patient preference. A positive response was defined as the patient either immediately looking to the right, as requested, or looking to the right after some period of hesitation. Of a total of 2309 patients seen, 1417 (61.4%) correctly looked to the right when asked. There was no significant difference (P=0.5552) between the sexes in correct left right discrimination, however, 285 out of 390 Welsh-speaking patients looked to the right (73.1%) vs 1132 out of 1919 (59%) English-speaking patients, which was statistically significant (P=0.0011).

We found that rates of correct left right discrimination among clinic attendees were significantly lower than previously published rates and that the potential for medical errors is thus higher than thought. Our observed variance in ability to lateralise may be due to, among other factors, hearing problems in our population with the more vocally distinct ‘Dde’ and ‘Chwith’, for right and left, respectively, in the Welsh language, being more easily understood.