Intraocular pressure and superior ophthalmic vein blood flow velocity in Graves’ orbitopathy: relation with the clinical features

The aim of this study is to evaluate the association of intraocular pressure (IOP) and superior ophthalmic vein blood flow velocity (SOV-BFV) with the clinical features of Graves’ orbitopathy.

During the 2002-2007 period, 66 eyes of 34 Graves’ orbitopathy cases were classified as mild, moderate and severe orbital disease, and evaluated according to their clinical features as: i)type 1 vs type 2 cases, and ii) cases with or without dysthyroid optic neuropathy. In all patients, a full ophthalmic examination including IOP and Hertel measurements was performed. SOV-BFV was analyzed with color Doppler sonography.

The Hertel value, IOP in primary and upgaze position were higher, and SOV-BFV was lower in moderate and severe Graves’ orbitopathy cases that showed statistical significance from mild cases, and controls (p = 0.001). Moderate and severe Graves’ orbitopathy cases showed comparable Hertel measures and IOP in primary and upgaze position (p = 0.39); however, SOV-BFV was significantly lower in severe cases when compared to moderate cases (p = 0.001).This study demonstrated statistically significant negative correlation between IOP in both primary (r = 0.43,p = 0.008) and upgaze position (r = 0.51,p = 0.002), and SOV-BFV. Additionally, statistically significant positive correlation was detected between Hertel values and SOV-BFV(r = 0.402,p = 0.007).There was a statistical difference between type 1 and 2 cases in Hertel values(p = 0.006), IOP in upgaze position (p = 0.026) and SOV-BFV (p = 0.003). SOV-BFV of the eyes showing dysthyroid optic neuropathy was statistically lower than eyes without dysthyroid optic neuropathy (p = 0.006).

IOP and SOV-BFV have significant association with the clinical features of Graves’ orbitopathy. The decrease in SOV-BFV increases the severity of Graves’ orbitopathy, and may have a role in the clinical course of dysthyroid optic neuropathy.