To evaluate differences between dominant and non-dominant eyes through analyzing refractive factors in determination of the dominant eye

Sixty-two subjects without underlying ocular disease were recruited. Ocular dominance was determined using the hole-in-the-card test. Uncorrected visual acuity, refractive error, and intraocular pressure (IOP) were checked in both eyes.

Mean uncorrected visual acuity of the dominant and non-dominant eye were 0.41 and 0.39, respectively. The number of patients whose uncorrected visual acuity of the dominant eye was superior to the non-dominant eye was 18(29%), and inferior to the non-dominant eye was 18(29%). Mean refractive power in the dominant eye was -3.2 diopter and -3.43 diopter degrees in the non-dominant eye, therefore no difference in degrees of myopia between the groups ( P =0.282) was observed. The number of patients whose dominant eye had a greater degree of myopia than the non-dominant eye was 24(39%) and the patients with a lower degree of myopia in the dominant eye was 32(52%). Astigmatism of the dominant eye was lower than the non-dominant eye in 35(56%) of the patients, thus a significant relationship was shown between astigmatism and the dominant eye ( P =0.0014). The mean IOP of the dominant eye was 15.4 mmHg and the non-dominant eye was 15.7 mmHg, showing no significant difference between eyes.

The dominant eye showed a lower degree of astigmatism than the non-dominant eye. The previous belief that myopia is more progressed in the dominant eye than the non-dominant eye because of excessive accommodative use of the dominant eye requires further study.