Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry. It occurs when the shape of your eye causes light rays to bend (refract) incorrectly, focusing images in front of your retina instead of on your retina.Nearsightedness may develop gradually or rapidly, often worsening during childhood and adolescence. Nearsightedness tends to run in families. A basic eye exam can confirm nearsightedness. You can compensate for the blur with eyeglasses, contact lenses or refractive surgery.

Symptoms

Nearsightedness symptoms may include: Blurry vision when looking at distant objects, The need to squint or partially close the eyelids to see clearly, Headaches caused by eyestrain, Difficulty seeing while driving a vehicle, especially at night (night myopia) Nearsightedness is often first detected during childhood and is commonly diagnosed between the early school years through the teens. A child with nearsightedness may: • Persistently squint • Need to sit closer to the television, movie screen or the front of the classroom • Seem to be unaware of distant objects • Blink excessively • Rub his or her eyes frequently

Causes

Your eye has two parts that focus images: • The cornea is the clear, dome-shaped front surface of your eye. • The lens is a clear structure about the size and shape of an M&M's candy. In a normally shaped eye, each of these focusing elements has a perfectly smooth curvature, like the surface of a marble. A cornea and lens with such curvature bend (refract) all incoming light to make a sharply focused image directly on the retina, at the back of your eye. A refractive error If your cornea or lens isn't evenly and smoothly curved, light rays aren't refracted properly, and you have a refractive error. Nearsightedness usually occurs when your eyeball is longer than normal or your cornea is curved too steeply. Instead of being focused precisely on your retina, light is focused in front of your retina, resulting in a blurry appearance for distant objects.