Mirror image myopic anisometropia in two pairs of monozygotic twins

Two sets of monozygotic twins with mirror image myopic anisometropia are reported. The first set were two boys aged 1 year 8 months. There was a right eye myopic anisometropia in one twin, and a left eye myopic anisometropia in the other. The differences in refractive power between both eyes were 11.6 and 7.6 dpt, respectively (spherical equivalent). The second set were two 6-year-old boys. The right eye had myopic anisometropia in one twin, while the left eye was affected in the other. The differences in refractive power between both eyes were 6.5 and 3.7 dpt, respectively (spherical equivalent). Exotropia was recognized in 3 cases. Previously only two sets of monozygotic twins with mirror image myopic anisometropia have been reported. Monozygotic twins with mirror image myopic anisometropia are extremely rare.