Cyclic esotropia

Presentation is made of a girl in whom the onset of cyclic esotropia with 48-h cycles occured at the age of 3 years. On the initial examination, the objective angle was +13 degrees whereas later it increased to 25-35 degrees in the phase of squinting. Binocular vision existed in the phase of orthophoria, but was absent in the phase of strabismus. The patient had good visual acuity, normal fundus finding and central fixation bilaterally. There was a minor hypermetropic refraction which decreased almost to emmetropia with time. Neuropediatric examination produced normal findings, and so were the VEP and EEG findings. A year later, the cycle deteriorated and strabismus became constant. Then, the eye with more pronounced strabismus was operated on. Postoperatively, low grade strabismus persisted and after one month decreased without any additional surgical intervention, eventually resulting in normal binocular vision. Five years later. the finding did not change, giving rise to hope that the condition would persist, i.e. that the child could be considered successfully treated. Cyclic esotropia or cyclic heterotropia probably is the most infrequent form oi strabismus, which is extremely rarely seen in practice. The etiology of the disease is unknown and has tentatively been related to the biological clock-mechanism in man.