symptoms may include: Seizures that begin in infancy and may worsen with age. Convulsions usually happen on the side of the body opposite the birthmark and vary in severity Intermittent or permanent muscle weakness Developmental delays and cognitive impairment Glaucoma (increased pressure within the eye) at birth or later. The increased pressure within the eye can cause the eyeball to enlarge and bulge out of its socket (buphthalmos) Migraines