Alright I’m gonna try to explain astigmatism, because this is an extreme example of what you might see at night if you have it. https://twitter.com/quitlarri/status/1279202481449373696

Astigmatism is all about the cornea. You can have astigmatism in the lens as well, but I want you to read this thread so let’s keep it simple

Somebody with NO astigmatism has a perfectly spherical shape to the cornea, like if you cut a basketball in half and sutured it to the front of the eye (unethical). Every ray of light entering the cornea would be PERFECTLY focused onto the retina allowing 20/20 vision.

Somebody with astigmatism has a cornea shaped more like a football, or for all you indoor kids, Arnold from Nickelodeon’s Hey Arnold. The curvature of the cornea is steeper in one direction and flatter in the other.

In a cornea with astigmatism, light rays entering the flatter part of the cornea will focus at one point (either in front of or behind or on the retina) while the light rays entering the steeper part of the cornea will focus at a totally different point.

Having the eye focus on different points will cause blurry vision. This is particularly noticeable when looking at lights at night. Streaks and starbursts are common because the eye cannot focus all the light rays at the same time like somebody with a basketball cornea can

Fortunately, this is correctable with glasses or contacts or LASIK or pumping up your eye because it’s a little low on air. Keep in mind that other things cause streaks and starbursts like cataracts or dry eye. Go see an eye doctor. Tell them a twitter ophthalmologist sent you