Refractive errors are conditions in which the shape of the eye prevents light from focusing properly on the retina, resulting in blurred vision. Common refractive errors include myopia, hyperopia, and astigmatism. Signs and symptoms of these errors include blurry vision, difficulty seeing at a distance, headaches, strain in the eyes, and squinting.

The cause of refractive errors is usually related to the shape of the eye, but can also be caused by changes in the cornea or lens. Diagnosis is typically done through a comprehensive eye exam, which includes a refraction test to measure the eyes’ ability to focus light.

Treatment for refractive errors often includes corrective lenses, such as glasses or contact lenses. In more serious cases, surgery may be recommended. LASIK and other types of laser eye surgery are often used to correct refractive errors. Other treatments include orthokeratology (or corneal reshaping) and intraocular lenses.