Squint surgery in TED -- hints and fints, or why Graves' patients are difficult patients.

Endocrine ophthalmopathy is the most common cause of acute onset diplopia in middle aged or older individuals. Ocular muscle involvement is characterized by myositis followed by fibrosis: this causes a stiffness and a shortening of the muscles involved with restriction of ocular movements: so the impairment of rotation is due to a mechanical obstacle and not to a paresis. Prisms are rarely useful in relieving diplopia and the majority of symptomatic patients need squint surgery. Timing of surgery is very important and two considerations are to be kept in mind: first, the systemic disease must be in remission and the ocular deviation must be stable for at least six months; second, if more than one surgical procedure is needed for the ophthalmopathy, muscle surgery has its right place after orbital surgery and before lid surgery. Obviously dealing with restrictive disorders, surgery is based on weakening procedures of the affected muscles: identifying the affected muscles is of crucial importance and may be sometime difficult for the presence of misleading signs; great advances have been made in surgical technique with the development of adjustable sutures and of topical anesthesia. Prognosis is usually good with more than 80% of patients recovering a useful field of binocular single vision with one procedure and more than 90% with two or more procedures.