Nyctalopia in antiquity: a review of the ancient Greek, Latin, and Byzantine literature.
OBJECTIVE: To investigate the original definition and use of the term nyctalopia in ancient medical literature in view of the controversy between the English and some continental European literatures. DESIGN: Historical manuscript. METHODS: We review the use of the term in ancient Greek, Roman, and early Byzantine medical literature (5th century BC-7th century AD) and include a quick reference to the theories on its etymology. RESULTS: Physicians of antiquity defined as nyctalopia the symptom of defective dark adaptation, most commonly in the clinical setting of vitamin A deficiency. An alternative definition, the improvement of vision at night, is not recorded before the 2nd century AD and seems to result from a broader interpretation of the word, lacking medical acceptance at that time. CONCLUSIONS: We propose to the ophthalmic community the use of the term nyctalopia exclusively for the description of defective dark adaptation.