Refractive Errors

Emmetropia : it's when the eyes see naturally well, without needing glasses or contact lenses. The image forms perfectly on the retina, allowing for clear vision both far and near. This is what is referred to as "normal" vision.

Myopia : it is a vision disorder where near vision is clear, but distant vision is blurry. This occurs because the image forms slightly in front of the retina, as the eye's optical power is too strong for its length. Myopia can be corrected with glasses/contact lenses or refractive surgery.

Farsightedness : it's a vision disorder where vision is generally clearer at a distance than up close, especially in young people. This occurs because the image forms slightly too far behind the retina. The eye has to make an effort to see clearly, which can cause eye strain and headaches. As with myopia, optical correction with glasses/contact lenses or refractive surgery can correct farsightedness.

Astigmatism : a vision disorder where images appear blurry or distorted, both up close and far away. This is caused by an irregular curvature of the cornea or lens. Glasses, contact lenses, or refractive surgery can correct astigmatism.

Presbyopia : With age, the lens loses its flexibility and can no longer sufficiently bulge to focus on near objects. This prevents light rays from focusing on the retina and makes near vision blurry.

Presbyopia can be corrected with glasses, contact lenses or refractive surgery.