latanoprost (xalatan), a prostaglandin, may significantly reduce iop (intraocular pressure) in patients with glaucoma associated with sturge–weber syndrome. latanoprost is commercially formulated as an aqueous solution in a concentration of 0.005% preserved with 0.02% benzalkonium chloride (bac). the recommended dosage of latanoprost is one drop daily in the evening, which permits better diurnal iop control than does morning instillation. its effect is independent of ethnicity, gender or age, and it has few to no side effects. contraindications include a history of cme, epiretinal membrane formation, vitreous loss during cataract surgery, history of macular edema associated with branch retinal vein occlusion, history of anterior uveitis, and diabetes mellitus. it is also wise to advise patients that unilateral treatment can result in heterochromia or hypertrichosis that may become cosmetically objectionable.