名詞 emmetropia:

1. (ophthalmology) the normal refractive condition of the eye in which there is clear focus of light on the retina

em.me.tro.pi.a

n.（名詞）
The condition of the normal eye when parallel rays are focused exactly on the retina and vision is perfect.
屈光正常：當(dāng)平行光線恰好聚焦于視網(wǎng)膜并形成清晰視覺時正常眼睛的狀態(tài)

來源：
Greek emmetros [well-proportioned, fitting] en [in] * see en- 2 metron [measure] * see meter 2
希臘語 emmetros [比例合適的，適合的] en [在…里] *參見 en-2 metron [測量] *參見 meter2
-opia
-opia

【引伸】
em.metrop.ic