Hyperopia, or farsightedness, has been one of the most challenging problems that we have faced. Also hyperopia is sometimes difficult for patients to understand. It is important to remember that hyperopia is basically opposite from myopia or nearsightedness. The things that cause an individual to become hyperopic are as follows:
The corneal curvature is too flat and/or the axial length of the eye is too short. Therefore we have an eye that usually has a combination of both a flat corneal surface and a small globe. The cornea of course is the front surface of the eye that is clear or transparent.
In a hyperopic individual, light rays that enter the eye are focused behind the retina instead of directly on the retina as in a normal eye. It is an inherited condition. It is present in childhood, but it does not usually become apparent to most people until they are in the late 30's, when they can no longer use their own muscles inside the eye to overcome it. Patients with hyperopia begin to have difficulty seeing things clearly in the distance or near unless they wear glasses or contact lenses or some other type of optical correction. As we grow older, we all start to have difficulty reading and may require reading glasses or a bifocal. This condition is known as presbyopia.
If a person has a very mild degree of hyperopia, this individual usually gets along fine until they reach 38-40 years of age.This is the origin of the term "farsightedness." At that time they will start noticing that their reading will become more difficult, and reading glasses will help this situation. However, if one is moderately or highly hyperopic, this can affect both near and distance vision. As you get older and older, your distance and near vision gets worse and worse. Basically what happens involves the accommodating process of the eye. The crystalline lens inside of the eye is involved in focusing the light rays onto the retina. When a person is farsighted, the crystalline lens has to be focused even for distance in order to pull the focal point back onto the retina in order to achieve clear vision. Therefore people who have moderate to high degrees of hyperopia can have "brow ache" or "eye strain" because the ciliary muscles that suspend the crystalline lens by tiny zonules (or strings) have to constantly flex in order to focus the light rays onto the retina.