Astigmatism in unilateral coronal synostosis: incidence and laterality

Unilateral coronal synostosis alters orbital development and can be associated with strabismus, oblique muscle dysfunction, astigmatism, and amblyopia. While the ocular effects are most dramatic on the side of the fusion, the shape of the contralateral orbit is also abnormal and the effect of these changes on bilateral visual development has not been fully described. The purpose of this study was to analyze the incidence and laterality of astigmatism in children with unilateral coronal synostosis.

We retrospectively reviewed the charts of 39 consecutive patients with unilateral coronal synostosis. Recorded data included the following: patient demographics, visual acuity, cycloplegic refraction, ocular motility, procedures for craniofacial and strabismus correction, and presence and treatment of amblyopia at each visit.

Twenty-one of 39 patients (54%) had 1.00 D or more astigmatism in at least one eye at their last recorded refraction. Sixteen of the 21 (76%) had aniso-astigmatism of 1.00 D or more. Of the 16, 14 (88%) had the greater degree of astigmatism in the contralateral eye. Fifteen of the 39 studied (38%) had amblyopia and, in 12 of these 15 patients (80%), the amblyopic eye was contralateral to the synostosis. Nineteen of 39 patients (49%) had greater ipsilateral fundus excyclotorsion, whereas only 1 of 39 (3%) had greater contralateral excyclotorsion.

Patients with unilateral coronal synostosis are at risk for developing a greater degree of astigmatism in the eye contralateral to the synostosis. Ocular disturbances in the contralateral eye, especially anisometropic amblyopia, must be considered when treating patients with this type of craniosynostosis.