a comparison between callahan and knapp procedure for hypotropia in double elevator palsy

twenty six patients with double elevator palsy (dep) (ranging from 25-90 pd), who had undergone either callahan or knapp-modified-kanpp procedure from february, 1981 to february, 1994, were reviewed. we achieved acceptable results in correction of hypotropia in primary position. three patients gained peripheral fusion and after reviewing the results we concluded that in patients having large-angle hypotropia with dep, especially when it is accompanied by inferior rectus restriction. callahan procedure is preferrable; however, in coexisting vertical-horizontal deviation, modified-knapp procedure is recommended.