Orbital complications of sinusitis.

The ethmoid and maxillary sinuses are the sinuses most frequently involved with orbital infections. Routes of spread are by direct extension through bone and indirectly through the valveless venous plexuses of the orbit, nose, and sinus. Classification of orbital infections can be thought of as either preseptal or postseptal and then further subdivided from there. The diagnosis has been greatly improved by the use of CT scans; however this should never be the only entity used for diagnosis. The determination of visual acuity (VA) is the single most important finding and will ultimately determine treatment modality. Orbital infections show different and more virulent bacteria than does non-complicated sinusitis and this should be reflected in the choice of medical and surgical therapy. Medical management is well accepted for infections without abscesses, and surgery is generally needed for infections with an abscess.