Mueller's muscle: to relax or to incise.

This is a cumulative clinical study of the effect of topical guanethidine sulfate solution. Two hundred fifty-six cases of patients with lid retraction secondary to thyroid orbitopathy or trauma were treated with guanethidine sulfate 5-10% solution before surgical intervention was considered. Eighty-five percent of thyroid-related lid retraction responded to guanethidine sulfate, whereas only 67% of the traumatic or iatrogenic cases responded to guanethidine sulfate. None of the patients showed overt reaction to guanethidine sulfate. The conservative management of lid retraction with topical guanethidine sulfate is relatively safe and mostly effective and should be considered before surgical intervention is considered.