Paranasal sinus diseases manifest themselves in a high percentage of eases by striking and threatening ocular and orbital signs and symptoms (Ducrey 1985; Duke-Elder 1972,1974; Ganz 1977; Herrmann 1958; Jakobiec and Jones 1986; Jakobiec et al. 1986; Seiferth and Wustrow 1977; Siegert 1975; Smith et al. 1986; Wustrow 1965). This explains why the ophthalmologist is often the first to see and to examine such patients. The anatomic basis of ophthalmic complications in paranasal sinus diseases is in the following (Jakobiec and Jones 1986): 1. The orbit is nearly completely surrounded by the sinuses, except laterally. 2. The separating bones are very thin. 3. There are numerous suture lines. 4. There is a direct communication between the ethmoidal cells and the orbit by the anterior and posterior ethmoidal vessels. 5. The orbital contents such as the extraocular muscles and the optic nerve are in close relationship to the sinuses. 6. The orbital veins lack valves, allowing for a free communication between the facial vein and the cavernous sinus.