Unilateral blepharochalasis is an extremely rare disorder with an unknown etiology and pathogenesis. The authors present a 22-year old patient in whom a right-sided skin overhang of the upper eyelid caused visual field impairment. The condition was corrected by a standard blepharoplasty. The histological examination suggested a localised anomaly of the lymphatic system and an almost complete absence of elastic fibres as the causative agent.