Hemianopsia - Hemianopsia

... Hemianopsia is when the right or left half of the visual field of both eyes is lost, with the boundary being a vertical line passing through the point of fixation. When the same side of both eyes is lost, it is called homonymous hemianopsia (there are right homonymous hemianopsia and left homonymous hemianopsia), and when the opposite side of both eyes is lost, it is called heteroonymous hemianopsia (there are bitemporal hemianopsia and binasal hemianopsia). In both cases, roughly half of the visual field is lost, but sometimes a quarter is lost, which is specifically called quadrant hemianopsia. ...

*Some of the terminology explanations that refer to "enonymous hemianopsia" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…　また，注視点を通る垂直線を境界として，両眼の視野の右半部あるいは左半部が欠損するものを半盲hemianopsiaという。両眼の同側が欠損するものを同名半盲homonymous hemianopsia(右同名半盲と左同名半盲がある)といい，両眼の反対側が欠損するものを異名半盲heteronymous hemianopsia(両耳側半盲と両鼻側半盲がある)という。いずれも視野のほぼ半分が欠損することが多いが，1/4が欠損することもあり，これをとくに四分の一半盲と呼ぶ。…

※「異名半盲」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