The OKN Response and Binocular Vision in Early Onset Strabismus

Joyce Mein, MBE DBO (T)

Asymmetry of Uniocular opto-kinetic nystagmus (OKN) occurs when a normal response is elicited by moving the targets in a temporal-nasal direction but not by moving them in a nasal-temporal direction. This finding has been reported in normal infants and in those with congenital esotropia.
In this study OKN has been investigated in 69 patients with early onset strabismus and in 25 patients with later onset strabismus. Asymmetry has been found only in those with strabismus, nystagmus and dissociated vertical divergence (DVD) and not in other patients with early or later onset strabismus. Although superficial binocular vision was found in some cases it was insufficient to maintain peripheral fusion.