Refractive errors: types and causes

In short: Refractive errors describe various forms of disturbed light refraction in the eye, where images aren’t sharply focused on the retina. The most common forms are nearsightedness, farsightedness, and astigmatism.

In more detail: With normal vision, incoming light rays are precisely focused on the retina, producing a sharp image.

Note: Not a substitute for medical advice.

In detail

• Nearsightedness (myopia): The eyeball is too long or the refractive power too strong, making distant objects appear blurry while close objects remain clear.
• Farsightedness (hyperopia): The eyeball is too short or the refractive power too weak, making close objects appear blurry.
• Astigmatism: An irregularly curved cornea causes light rays to focus at multiple points rather than a single point.
• Presbyopia: With increasing age, the eye’s lens loses elasticity, making it harder to focus on nearby objects.
• Genetic factors: Nearsightedness tends to run in families, indicating a hereditary component in its development.
• Environmental factors: Spending a lot of time outdoors and less near-work in childhood is associated with a lower risk of nearsightedness.
• Correction options: Glasses, contact lenses, and refractive eye surgery offer different correction options depending on the type and severity of the refractive error (sinnesorgane-auge-ohr-nase, nervensystem-aufbau-und-funktion).