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Refractive errors: blurry vision, the four types, the eye exam, and glasses, contacts or surgery
For anyone who squints to see far away, holds a phone or a book farther away to read, gets headaches or tired eyes from reading or screens, sees glare or halos around lights at night, still sees blurry with their glasses or contacts, has a child who may need glasses, or cannot afford an eye exam. The National Eye Institute (NEI, part of the NIH) says refractive errors are the most common type of vision problem: more than 150 million Americans have one, but many don’t know they could be seeing better, and that is why eye exams are so important. This page passes on, by name, what NEI says: the signs, nearsightedness, farsightedness, astigmatism and presbyopia, who has them and what causes them, the eye exam, and glasses, contact lenses and surgery. It builds the words to say to an eye doctor, and prints a card to keep.
Right now
- A sudden change in your sight, eye pain, or suddenly a lot of new floaters, flashes of light, or a curtain over your sight? That is not a refractive error to wait on: go to an eye doctor or an emergency room now (the retinal detachment page), and call 911 in an emergency. A hurt eye: the eye injury page (ours).
- Can’t afford an eye exam or glasses? The eye care page lists free and low-cost programs (ours).
- Thoughts of suicide? Call or text 988, any hour (ours).
More help
- Linked to it, on this site: Eyes and sight: find the right page · Eye care you can afford · Low vision · Retinal detachment · Cataracts · Dry eye · An eye injury.
- Care and costs: When you need a doctor and can’t pay · Get ready for your appointment.
- In a crisis: Help right now (988, 911). All our free tools.
Your eyes or your sight, and not sure this is the right page? The pages on this site for a hurt or pink eye, glaucoma, cataracts, diabetes and the eyes, macular degeneration, a detached retina, dry eye, fading sight and eye care you can afford, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 16, 2026 on five National Eye Institute (NIH) pages: Refractive Errors (last updated December 19, 2025), and Nearsightedness (Myopia), Farsightedness (Hyperopia), Astigmatism and Presbyopia (each last updated December 4, 2024). Ours: that a sudden change in sight, eye pain, or a lot of new floaters, flashes or a curtain is not something to wait on, and 911 in an emergency; the eye injury page; 988 for thoughts of suicide; that glare can have other causes, like cataracts; asking whether it is safe to drive; what to bring to the eye exam and asking for a copy of your prescription; the questions to ask; low-cost eye exams and glasses; and the order of the steps. What we left out: NEI’s research news, its statistics page, and its separate pages on eyeglasses, contact lenses and surgery (not read for this guide). Where NEI’s pages give different ages for presbyopia, we use the Presbyopia page: usually after age 45. This page saves nothing and loads no trackers.