How does nearsightedness occur?

Answer 1

These conditions are caused by the shape of the eyeball, which changes as people get older. But you can have either condition regardless of your age, a lot of it is based on family medical history.

Answer 2

Both are common eye problems solved with glasses or contacts. Nearsightedness is called myopia, and farsightedness is known as hyperopia. The main biological difference in the two is that in myopia, the images seen are focused in front of the retina, rather than directly on the retina. In hyperopia, the images are focused behind the retina, rather than on top of it.

Answer 3

This is an extremely common problem across the globe. Being nearsightedness, or myopic, affects billions of people and the prevalence of myopia is nearly epidemic in areas of Asia. However, there can come a time in one's life where they are BOTH nearsighted yet have difficulties with near vision as well and will need different corrective lenses to treat both conditions.

Being myopic occurs when light does not focus directly onto the specialized neural tissue at the back of the eye called the retina. This occurs because the cornea is essentially too steep for how long the eyeball is. A person who is myopic will have difficulty seeing objects at a distance. When wearing refractive correction such as glasses or contact lenses, you will usually be able to see clearly at all distances afterwards up to a certain age. When looking at objects up close, the eye will change focal power to see near objects by changing the shape of the lens inside the eye. This process is known as accommodation.

Unfortunately, as one ages the lens inside the eye becomes more rigid and can no longer change focal power as fluidly. When this occurs, you will have difficulty focusing on objects up close. In this scenario, the myopic individual can have problems with seeing both objects up close and at a distance. This is known as presbyopia and refers to the change in the lens inside the eye that can make a nearsighted person also "farsighted." The remedy for this can include bifocals, trifocals, progressive lenses, monovision, and multifocal contact lenses. Many nearsighted individuals may even prefer to remove their glasses when looking up close and using them to see objects at a distance.

Answer 4

Nobody knows for certain. Medina's theory is the best explanation of nearsightedness and farsightedness available.