Current methods of medical treatment of this difficult condition are briefly reviewed, with comments on the generally unsatisfactory response. Attention is therefore directed to surgical methods and a short history given of the various routes used for orbital decompression. The author's own results of transantral, and more recently ethmoidal, decompression are given, with a detailed description of the technique for the latter approach. An interesting frequent consequence of postoperative A pattern to the ocular movements is discussed in the light of Koornneef's concept of orbital fascial anatomy, and suggestions are made for its avoidance.