Effect of Thyroxine on Exophthalmos in Thyrotoxicosis

Exophthalmos is found in approximately 75% of patients with thyrotoxicosis (Buchanan et al., 1962). In a few patients the exophthalmos is severe and associated with chemosis, periorbital oedema, and ophthalmoplegia (Brain, 1959), whereas in the majority of patients the exophthalmos is of mild degree and constitutes little more than a cosmetic problem. The distinction between these two forms of exophthalmos is, however, arbitrary, since the mild form may occasionally progress to the severer variety (Werner, 1960). There is a tendency for both mild and severe exophthalmos to increase after treatment of thyro toxicosis, whether by surgery (Bartlett, 1962), radioiodine (Hamilton et al., 1960), or antithyroid drugs (Beierwaltes, 1948 ; Alexander et al., 1961), although clinical recognition of this tendency may be masked in the milder form by improvement in other eye signs such as lid-retraction (Hales and Rundle, 1960). Thyroxine has been claimed to be of benefit in the treat ment of severe exophthalmos (McCullagh et al., 1958). It has been suggested that thyroxine might also be of value in prevent ing increase in exophthalmos when administered along with antithyroid drugs in the treatment of thyrotoxicosis (Fraser, 1956 ; Bergfeit et al., 1961). In tne present paper we have studied the effect of L-thyroxine on the exophthalmos of thyro toxic patients treated with antithyroid drugs or radioiodine.