Predictability of Visual Function and Nerve Fiber Layer Thickness by Cross-Sectional Areas of Extraocular Muscles in Graves Ophthalmopathy

PURPOSE: To evaluate the predictability of visual function and peripapillary nerve fiber layer thickness by cross-sectional areas of extraocular muscles in patients with Graves ophthalmopathy. DESIGN: Interventional case series. METHODS: The data on a total of 76 patients with Graves ophthalmopathy were collected, and the cross-sectional areas of 4 rectus muscles were calculated using computed tomographic images. This study measured the correlation between the cross-sectional area of all rectus muscles and the Hertel value, logarithm of the minimal angle of resolution (logMAR), mean deviation of retinal sensitivity, P(100) value of visual evoked potential, total error of the Farnsworth-Munsell 100-hue color sensation test, and total thickness of the peripapillary nerve fiber layer thickness by optical coherence tomography. RESULTS: The cross-sectional area of all rectus muscles was significantly correlated with the mean deviation of retinal sensitivity (Pc = .08), the P(100) value of visual evoked potential (Pc < .01), and the total error of the 100-hue color sensation test (Pc < .01). However, the cross-sectional area of all rectus muscles was not significantly correlated with logMAR or proptosis, nor with the total thickness of the peripapillary nerve fiber layer. CONCLUSIONS: For patients with Graves ophthalmopathy, the cross-sectional area of all rectus muscles was significantly correlated with visual function. The enlargement of extraocular muscles can be an early sign of optic neuropathy prior to perceived clinical symptoms. Furthermore, it is possible to predict visual function change using the cross-sectional area of all rectus muscles. (Am J Ophthalmol 2011;151:901-906. 2011 (C) by Elsevier Inc. All rights reserved.)