Symptoms

Nearsightedness signs or symptoms may include:

• Blurry vision when looking at distant objects
• The need to squint or partially close the eyelids to see clearly
• Headaches
• Eyestrain

Children may have difficulty seeing things on white boards or screen projections in the classroom. Younger children might not express difficulty seeing, but they may have the following behaviors that suggest difficulty seeing:

• Persistently squint
• Seem unaware of distant objects
• Blink excessively
• Rub their eyes frequently
• Sit close to the television

Adults with myopia may notice difficulty reading street signs or signs in a store. Some people may experience blurry vision in dim light, as with nighttime driving, even if they see clearly in daylight. This condition is called night myopia.

Causes of myopia

Myopia occurs when the eye is effectively too long – so the distance between the cornea (the clear window at the front of the eye) and the retina (the light-sensitive tissue at the back of the eye) is too far. This means that light entering the eye is focused before it reaches the retina, which causes blurred vision.

In some cases, it could be due to the shape of the cornea, or the thickness of the lens inside the eye.

There is a huge amount of research, both past and present into the causes of myopia. It is currently believed that hereditary factors are the most important. You are far more likely to develop myopia if one of your parents has it. However, the picture of who will or will not develop myopia is far from clear.