Here are Some Common Conditions That Prevent People From Seeing Well
Your eye doctor may refer to your vision problem as your refractive error, or focusing problem.
In a normal eye, the focus comes to a point on the retina. But sometimes this does not occur. The result? Various forms of vision problems. Vision problems fall into one of two basic groups: low-order aberrations and high-order aberrations.
1. LOW-ORDER ABERRATIONS
1.1. Myopia (Nearsightedness)
Also known as nearsightedness, myopia is a condition in which you can see nearby objects well, but ob jects at a distance appear blurred.
1.2. Hyperopia (Farsightedness)
People with hyperopia, or farsightedness, see distant objects more clearly than nearby objects when they are young but may have difficulty with both as they get older.
Many individuals with myopia or hyperopia also have some degree of astigmatism. People with significant astigmatism experience blurred or distorted vision with all objects, whether near or far.
Presbyopia is the age-dependent need for reading glasses or bifocals. After age forty, and in most people by age forty-five, the ability to focus on an object close up, such as a restaurant menu, becomes more difficult. This happens to everyone. It is due to a loss of flexibility in the lens and a weakening in the muscles that enable the lens to flex and fine-tune the focus.
2. HIGH-ORDER ABERRATIONS
Higher-order aberrations, which are a result of subtle irregularities in the focusing mechanism of the eye, cause a loss of crispness, clarity, and contrast. Higher-order aberrations are focusing problems that are not correctable with glasses or contact lenses.