Christmas Eye refers to a poorly understood seasonal epidemic of corneal ulceration which predominantly occurs only within a particular region of Australia.
Circumstantial evidence suggests that beetles in the genus Paederus Staphylinidae and other beetles in the genus Orthoperus Corylophidae release chemicals, including pederin, that cause painful, but temporary, eye lesions when the beetles accidentally fly into a persons eye. They can also cause severe dermatitis and the so-called whiplash stripe across the skin.
Christmas Eye typically presents with a unilateral, irregular desquamation of the cornea with a well demarcated border. The defect stains brightly with fluorescein. In the very early stages the desquamation may be patchy before progressing to involve up to 80% of the corneal surface.
Early research suggests that individuals located within south-west New South Wales and north-east Victoria during the summer period are more frequently affected than elsewhere in Australia. Patients often describe being near a body of water the previous evening and the first cases usually occur when the daytime temperature approaches 30C - typically late November.