Near reflex

…The pupil is a small opening in the center of the iris, and its size changes due to the action of the pupillary sphincter muscle that surrounds the pupil in a circular shape and the pupillary dilator muscle that runs radially. The pupillary reflex is mainly the light reflex that changes the size of the pupil depending on the intensity of light, but there are also other reactions such as the near reflex, in which the pupil constricts when looking at something close, and the pupil dilates in response to mental excitement or pain. The light reflex occurs through the following mechanism. …

*Some of the terminology that refers to the "near vision reflex" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…瞳孔は虹彩の中心にある小孔で，その大きさは瞳孔を環状にとりまく瞳孔括約筋と放射状に走る瞳孔散大筋の作用によって変化する。瞳孔反射は主として，光の強さに応じて瞳孔の大きさを変える対光反射をいうが，ほかに近くをみると瞳孔が縮小する近見反射や，精神的興奮や痛み刺激で散大する反応もある。対光反射は次のような機序で起こる。…

※「近見反射」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報