The influence of localization, size and shape of the simulated intraorbital tumors on orbital veins.

The extent of changes in orbital veins depends primarily on the size of the space-occupying lesion. Large tumors, irrespective of their position, produced change in the orbital vein, but among small tumors only the superior and medial tumors produce slight changes in the orbital vein. Localization of the tumor is also an important factor. The superior tumors are characterized by the angle between the 2nd 3rd SOV segments not exceeding 100 degrees and by the quadrangle surface of 419 mm2 in average. The inferior tumors elicit slight changes in SOV. The medial tumors cause an increase of the angle between the 2nd and 3rd SOV segments above 130 degrees and the surface area of SOV quanrangle up to 550 mm2. The most characteristic feature of the intraconic tumors is the normal X point position. Shape of the tumor plays a minor role in producing changes in orbital veins.