The Effects of Horizontal Recti Surgery on Clinical and Paraclinical Indices in Congenital Nystagmus

To determine the effect of horizontal recti surgery on visual acuity and head posture and electronystagmographic indices in patients with congenital nystagmus. This prospective comparative case series was conducted on 58 patients with congenital nystagmus who were referred to our clinic over three years. Patients were divided into three groups: the first group (29 cases) had head posture less than 20°, binocular visual acuity (BVA) less than 20/30 and tropia less than 30D who underwent large recess of four horizontal rectus muscles; the second group (23 cases) had head posture less than 20°, BVA < 20/30 and tropia more than 30D who underwent large recess of two horizontal rectus muscles; and the third group (6 cases) had head posture more than 20° with any BVA or tropia who underwent Kestenbaum-Anderson surgery. Mean age of the patients was 18.7±9.1 years and mean follow-up period was 17.5±7.4 months. Visual acuity improved in all groups which was statistically significant in the 2-rectus group (P=0.0001). The speed and amplitude of nystagmus waves were decreased in all groups which were statistically significant in the 4-rectus group (P=0.02 and 0.04 respectively). A small myopic shift was seen in the 2-rectus and 4-rectus groups and a small hyperopic shift was found in the Kestenbaum-Anderson group. Statistically significant (P<0.001) improvement was achieved in eye deviation in the 2-rectus group and in head posture in the Kestenbaum-Anderson group. Horizontal recti surgery in congenital nystagmus can improve visual acuity, strabismus and abnormal head posture, especially with 2-rectus recession. Nystagmus intensity indices improve especially with 4-rectus recession.