Retrobulbar blood flow in idiopathic dilated episcleral veins and glaucoma.
ABSTRACT Dilated episcleral veins may occur in the presence of orbital tumors, carotid cavernous sinus fistula and other orbital obstructive lesions.
A 39-year-old man had a history of a red left eye for two years. The visual acuity was 20/20, episcleral and conjunctival veins were dilated, and both the intraocular (24 mmHg) and episcleral venous (18 mmHg) pressures were increased. The canal of Schlemm was filled with blood, and glaucomatous damage was pronounced in the optic nerve head and the visual field of the left eye. The retrobulbar blood flow in the left eye was normal in the ophthalmic and central retinal arteries, but markedly decreased in the central retinal vein. There were no signs of fistula or shunts. The right eye was without any pathology. MR and catheter angiography of the head and orbit were both normal.
Following trabeculectomy, the intraocular and episcleral venous pressures dropped to 9 mmHg and 8 mmHg, respectively, at 6 months follow-up. The episcleral and conjunctival venous congestion regressed, and the blood flow in the central retinal vein increased.
The reason for the observed clinical picture (Radius-Maumenee syndrome) and haemodynamic improvement after reduction of the intraocular pressure is not clear. We outline a hypothesis involving an increase of the vascular resistance in the vortex veins and the superior ophthalmic vein with a shift in local blood volume and vascular pressure due to high intraocular pressure.