Patent ID: 7441900

Claim:
A contrast chart device, comprising: a contrast target presenting part for presenting a contrast target changing a contrast for a contrast sensitivity test at prescribed timing; a pupil data measuring part for producing an image of an anterior ocular segment of a subject and measuring the diameter or area of a pupil region in said anterior ocular segment; and a measurement timing forming part for forming timing at which said pupil data measuring part performs measurement based on said prescribed timing, wherein said contrast target presenting part has: background illumination adjusting means for adjusting illuminance of a background illumination of said contrast target or contrast targets in order to maintain the retinal illuminance of said subject at generally prescribed value; and background illumination control means which receives the diameter or area of said pupil region of said subject measured by said pupil data measuring part and sends a background illumination control signal to said background illumination adjusting means so that the diameter or area of said pupil region will be a prescribed value.