Right head tilt with shak...

A 10-year-old child presented with head tilt to the right and shaking movement of eyes since birth. On examination, his best-corrected visual acuity was 20/80 and N6 at 10 cm in each eye. Cycloplegic refraction with 1.0% cyclopentolate and 0.5% tropicamide was + 1.5 diopter sphere/−2.5 diopter cylinder at 180° in both eyes. He had a right head tilt of 25° as measured with goniometer (Figure 1a). There was horizontal, low-amplitude, and low-frequency right beating jerk nystagmus, decreasing on right head tilt and increasing on left head tilt and dampening on convergence. With glasses, the child was orthotropic. There was no torsion of the fundus in either eye. The stereoacuity was 400 seconds of arc by Titmus fly test. For correcting the head tilt, superior oblique (SO) anterior tenectomy was performed in the right eye [weakening right SO (RSO)], Harada–Ito procedure for SO in the left eye (strengthening left SO), and inferior oblique (IO) recession in the left eye (weakening left IO) under general anaesthesia.