FIGURE 9.

Periocular port-wine stain development and distribution. Cavernous sinus venous hypertension transmitted to the superior ophthalmic vein and its anastomoses with the nasofrontal and angular veins will cause port-wine stain involvement of the upper eyelid. Since the inferior ophthalmic vein, however, also drains into the pterygoid plexus proximal to the globe, venous pressure in the inferior ophthalmic vein distal to this juncture is much reduced, and port-wine stain involvement of the lower eyelid is less common.