名詞 astigmatism:

1. (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea
   同義詞：astigmia
2. (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point
   同義詞：astigmia

a.stig.ma.tism

n.（名詞）
A refractive defect of a lens or other optical system that prevents light rays from converging at a single point, resulting in a blurred or imperfect image.
散光：有折射缺陷的透鏡或其它光學(xué)系統(tǒng)，阻礙光線匯聚于一個焦點(diǎn)，形成一個模糊或不完全的圖象
A visual defect in which the unequal curvature of one or more refractive surfaces of the eye, usually the cornea, prevents light rays from focusing clearly at one point on the retina, resulting in blurred vision.
亂視，像散：一種視力缺陷，眼球表示面一點(diǎn)或多點(diǎn)折射時屈光不均，通常為角膜，使光線不能清晰地在視網(wǎng)膜上聚為一個焦點(diǎn)，從而導(dǎo)致視力模糊不清

來源：
a-
a-
Greek stigma stigmat- [point] from stizein stig- [to tattoo] * see steig-
希臘語 stigma stigmat- [尖端，點(diǎn)] 源自 stizein stig- [刺青] *參見 steig-

【引伸】
as.tigmat.ic
as.tigmat.ically
adv.（副詞）