She has had her sight restored thanks to a corneal transplant.通过角膜移植手术，她恢复了视力。In advanced cases of keratoconus, corneal transplant surgery is required.严重圆锥形角膜需要做角膜移植。One or both eyes cannot filter light properly because the corneal surface is irregular.因为角膜表面异常，一只眼睛或双眼均无法正常过滤光线。