Vision problems such as farsightedness and nearsightedness happen when eye shape affects focus.
What are refractive errors?
The cornea and lens of your eye help you focus. Refractive errors are vision problems that happen when the shape of the eye keeps you from focusing well. The cause could be the length of the eye (longer or shorter), changes in the shape of the cornea, or aging of the lens.
Four common refractive errors are:
- Nearsightedness (myopia) – clear close-up vision, but blurry distance vision
- Farsightedness (hyperopia) – clear distance vision, but blurry close-up vision
- Presbyopia – inability to focus close up as a result of aging
- Astigmatism – focus problems caused by the cornea
The most common symptom of refractive errors is blurred vision. Other symptoms may include double vision, haziness, glare or halos around bright lights, as well as squinting, headaches or eye strain.
Glasses or contact lenses can usually correct refractive errors. Laser eye surgery may also be a possibility.
Source: NIH: National Eye Institute