Of course, it does. The cornea is a transparent and clear membrane protection layer on eyeball. It is transparent so that the light could travel through and focus onto retina, which is how we can see with eyes. Any scarring of cornea will make it opacity. Once the cornea becomes opacity, light can't travel through and focus on the retina, so the vision is impaired. Imagining with covered camera shot, can you take any picture with it? This is why corneal scarring would impair vision. According to some report, only new born infants could grow the corneal scarring off. As to other people, once the scarring impacts the vision enough, a surgery is required. So doctor will have patients after intraocular surgery to wear sunglasses to avoid corneal scarring.