Ophthalmic instrument for measuring optical quality of eye

An ophthalmic instrument for measuring optical quality of an eye, comprising:

• a multi-element eyepiece and a rotatable mirror, wherein
• a mirror surface of the rotatable mirror is optically conjugated with a first focal plane in an object space of the multi-element eyepiece through a first lens, to adjust an angle of light entering the eye, wherein the first lens is arranged between the multi-element eyepiece and the rotatable mirror, and a focal point of the first lens is arranged in a virtual focal plane in an image space of the multi-element eyepiece, such that light incident to or emitted from the first lens is collimated and the multi-element eyepiece and the first lens function as a telescope system, and
• the multi-element eyepiece comprises an eyepiece, a field lens and a second lens arranged in sequence, and the field lens comprises a third lens a fourth lens and a fifth lens arranged in sequence, wherein the eyepiece, the third lens, the fourth lens and the fifth lens each is a positive lens, and the second lens is a negative lens.