Evaluation and Spectrum of Orbital Diseases

Although orbital disorders are not frequently encountered in the comprehensive ophthalmologist’s practice, it is essential to be able to diagnose patients with orbital disease and manage them accordingly. Various disease processes can affect the orbit. This chapter endeavors to provide a thoughtful, stepwise, and logical approach to the evaluation of orbital disease. The discussion begins with differential diagnosis, adds an intelligent history-taking and physical examination, and then focuses on efficient use of diagnostic tests to finally arrive at the correct diagnosis. The staging and management of two common orbital disorders, orbital inflammation and thyroid-associated ophthalmopathy, will also be discussed. The differential diagnosis of orbital disease is extensive, and most listings of orbital disease divide the causes between histopathologic and mechanistic categories. This type of grouping is intellectually sound and scientifically useful but does not provide a framework that the clinical practitioner can easily grasp and directly use in sorting through the differential diagnosis of any given patient. In broad terms, orbital disease can be considered in terms of location, extent, and biologic activity. The classification used in this chapter is broken down along clinical lines and takes advantage of the fact that the orbit has a somewhat limited repertoire of ways that it can respond to pathologic conditions. Orbital disease can be categorized into five basic clinical patterns: inflammatory, mass effect, structural, vascular, and functional. Although many cases cross over into several categories, the vast majority of clinical presentations fit predominantly into one of these patterns. As the clinician walks through each step of the evaluation process—history, physical examination, laboratory testing, orbital imaging—a conscious effort should be made to categorize the presentation within this framework. If the practitioner approaches orbital disease with this framework of discrete patterns of clinical presentation, then at every step of the diagnostic pathway (history, physical examination, orbital imaging studies, and special tests), he or she can draw from a defined set of differential diagnoses that characterize each pattern of orbital disease and use that information to efficiently and confidently orchestrate diagnosis and management.