sclera
Anatomical term for the white outer layer of the eyeball. Used in medical and biological contexts.
The sclera forms the white part of the eyeball.
scleritis
Standard kanji form for 'sclera' in medical contexts.
Rare variant using the non-jōyō kanji 鞏; not commonly encountered.
From 強 (strong, hard) + 膜 (membrane), referring to the tough outer membrane of the eye.