The pigmented,round,contractile membrane of the eye,suspended between the cornea and lens and perforated by the pupil. It regulates the amount of light entering the eye.

• 虹膜眼睛中一层带色素的，球形的可伸缩的薄膜，处于角膜和晶状体之间，为瞳孔所穿过。它调节进入眼球的光的数量。