PURPOSE. Glaucoma Overlap Syndrome has been recently identified as the sequential appearance of two or more risk factors for glaucomatous damage over time. Dr. Robert Ritch coined the term "overlap syndrome" when he described a group of patients with both pigmentary dispersion and exfoliation syndrome. Here we are extending the concept of overlap syndrome to encompass patients with glaucomatous, as well as non-glaucomatous, optic neuropathy.
METHOD. This retrospective study concentrates on specific etiologies that were selected by the author through an extensive chart search. Along with a comprehensive examination, an extended testing battery was performed, including B-scan, MRI/CT, threshold visual fields, GDx, and HRT. RESULTS. Thus far, we have identified at least 50 patients with both glaucomatous and non-glaucomatous optic neuropathy. Some of the etiologies we have encountered include: idiopathic anterior ischemic optic neuropathy, multiple sclerosis, optic nerve hypoplasia, Leber''s hereditary optic neuropathy, tilted disc syndrome, myopic degeneration, optic disc drusen, optic pits, sarcoid optic neuropathy, thyroid orbitopathy, autoimmune optic neuropathy, and migraine headaches. Exemplary cases will be presented.
CONCLUSIONS. It is imperative for the clinician to recognize that patients may have nerve fiber loss due to more than one etiology, which may present either simultaneously or sequentially. Since some of these etiologies may respond to treatment, irreversible loss of optic nerve fibers can be prevented with a timely diagnosis.