Article Text

Download PDFPDF
Nyctalopia and hemeralopia: the current usage trend in the literature
  1. N Ohba1,
  2. A Ohba2
  1. 1The Division of Orthoptics and Visual Science, Faculty of Medical Welfare, Aichi Shukutoku University, Nagoya-shi, Japan
  2. 2Department of Language Communication, Graduate School of Communication, Aichi Shukutoku University, Nagoya-shi, Japan
  1. Correspondence to: N Ohba Asahigaoka 109-3, Minamisakae-machi, Owariasahi-shi 488-0046, Aichi-ken, Japan; ohbanm{at}

Statistics from

Nyctalopia and hemeralopia are the rare examples of words that may lead to a good deal of controversy and confusion among doctors of different linguistic backgrounds, because of different definitions and meanings. Nyctalopia is a word from the Greek medical antiquity, defined as “night blindness” or defective dark adaptation.1 Hemeralopia is a word that originated in the 18th century, which means “day blindness” or visual defect characterised by the inability to see as clearly in bright light as in dim light.2,3 Standard English dictionaries also conform with the meanings of nyctalopia and hemeralopia as night blindness and day blindness, respectively. However, …

View Full Text


  • Competing interests: None declared.

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.