Prolonged Constant Eye Misalignment Leads to Failure to Develop Binocular Vision in Childhood Ocular Myasthenia Gravis

Abstract

Variable eye misalignment and blepharoptosis in childhood ocular myasthenia gravis can lead to permanent binocular visual loss. However, a standard ophthalmologic intervention for this condition has yet to be fully established. This study investigated the influence of variable eye misalignment and asymmetric blepharoptosis on the development of binocular vision in childhood ocular myasthenia gravis. The authors retrospectively reviewed clinical records of consecutive patients with childhood ocular myasthenia gravis whose age of onset was younger than 36 months and who had follow-up periods of more than 1 year. Five patients were enrolled and were treated medically with pyridostigmine or corticosteroids. Eye alignment, eye movements, and blepharoptosis were observed during the follow-up period. Stereoacuity was recorded before and at the end of follow-up using Titmus stereoscopic and major amblyoscopic tests. None of the patients had amblyopia or anisometropia, but all had blepharoptosis that improved within 2 weeks after medication was administered. There was only one case in which stereoacutiy failed to develop, and this patient had a long period of constant exotropia lasting 48 months. In the remaining four cases, there was constant exotropia lasting less than 4 months or intermittent exotropia throughout the follow-up period. All of these patients regained or maintained binocular vision. Prolonged constant eye misalignment may be attributable to impaired binocular vision, and prompt eye alignment may be necessary in childhood ocular myasthenia gravis. Therefore, treatment based on precise assessment by a neuro-ophthalmologist or pediatric ophthalmologist that evaluates even slight eye misalignment is essential in ensuring normal development of binocular vision.