Adult with Acquired Diplopia at Distance: Do I Image? Do I Operate? (Video)

Adult onset divergence insufficiency (DIET) is a well-recognized condition that appears to be more prevalent now that the population is aging and staying more active. DIET is a more recent descriptive term of the clinical findings, but has also been referred to as "Divergence weakness in adults", "Age related distance esotropia," "Distance esotropia in the elderly," and a variation of "Sagging eye syndrome." Initially DIET was thought to be a mild 6 nerve palsy and neuro-ophthalmologists tended to evaluate these patients with neuroimaging, systemic work up, (including myasthenia and thyroid associated orbitopathy), and possibly lumbar puncture testing. In most cases, these tests are non-diagnostic. However,anatomical and high resolution orbital imaging studies performed by Joe Demer et. al. show that the pathophysiology is most likely involutional changes in the connective tissue band between the lateral rectus and superior rectus muscles (LR/SR band). This causes the lateral rectus muscle and its orbital pulley to sag inferiorly and thus diminish its ability to abduct at distance. Thus if neuroimaging is to be obtained, coronal fine cuts of the orbit are necessary to demonstrate the inferior displacement of the latera rectus and often the stretching or the LR/SR band with nasal displacement of the superior rectus. In some elderly patients with underlying neurodegenerative diagnoses such as Parkinsonism, DIET may occur from a neurological etiology.