astigmatism
Medical term for a refractive error where the eye does not focus light evenly onto the retina, causing blurred or distorted vision.
Because of my astigmatism, car headlights look blurry at night.
I was diagnosed with astigmatism at the eye clinic.
乱視 is astigmatism, a distinct vision problem (blurring from an irregular eye shape) that is often confused with or co-occurs with 近眼.
irregular astigmatism
Compound of 乱 (ran, 'disordered') and 視 (shi, 'vision'), referring to the irregular curvature of the eye's lens or cornea.