Farsightedness is a vision problem (or refractive error) that usually causes near vision to be blurred while distance vision remains normal. But farsightedness can affect your vision in different ways, depending on your age and the amount of farsightedness you have.
Young individuals with mild or moderate farsightedness can often see clearly at all distances. Instead of causing blurred near vision, their farsightedness may cause only headaches and eyestrain. Older individuals – even those with relatively mild farsightedness – may find that farsightedness causes blurred vision at all distances (both near and far).
Farsightedness is often confused with presbyopia. Presbyopia is the normal age-related loss of near focusing ability due to hardening of the crystalline lens inside the eye. This change usually becomes noticeable after age 40 and gets progressively worse over a period of several years. Presbyopia is corrected with reading glasses (for people who need no corrective lenses for distance vision or who wear contact lenses for distance vision) or with bifocal, trifocal, or progressive eyeglass lenses (for people who already wear eyeglasses).
Farsightedness, on the other hand, usually occurs early in childhood and remains relatively constant throughout a person’s lifetime. Everyone experiences presbyopia (if they live long enough). Not everyone experiences farsightedness.
The medical term for farsightedness is hyperopia.
What causes farsightedness?
Clear vision requires the cornea and the lens of the eye to focus light perfectly on the retina. For this to happen, the cornea and lens must have exactly the right amount of curvature so they can focus light within the length of the eyeball.
Farsightedness occurs when the cornea (or lens, or both) is not curved enough to bring light to a focus within the length of the eyeball. In some cases, the cornea and lens have a normal amount of curvature, but the eyeball is smaller than normal and therefore does not provide enough front-to-back distance to match the focus distance of the cornea and lens.
A young person can compensate for some degree of farsightedness by focusing harder with their eyes – a process called accommodation. This explains why some individuals in their teens and twenties can have a significant amount of hyperopia and still see clearly without corrective lenses. But overuse of the focusing muscle inside the eye can cause frequent headaches and eyestrain.
The older a person gets, the more difficult it is to overcome farsightedness with extra accommodation. Eventually, vision becomes blurred and corrective lenses are required for clear vision.
How common is farsightedness?
About 30 percent of Americans are farsighted.
What are the symptoms of farsightedness?
Mild farsightedness may produce no symptoms in children and young adults. Moderate or severe farsightedness in all age groups (and mild hyperopia in older adults and some younger individuals) can cause one or several of the following symptoms:
- Headaches (especially during and after reading and other close work)
- Eyestrain or fatigue (especially during and after reading and other close work)
- Blurred vision (especially up close)
- Poor concentration and/or reading comprehension problems in school
Who is at risk?
Anyone can have farsightedness. A family history of hyperopia is an added risk factor.
How is farsightedness detected?
Farsightedness is detected by a comprehensive eye exam performed by an optometrist or ophthalmologist.
Farsighted children can sometimes pass a school vision screening. For this reason, all children should have a professional eye exam prior to beginning school to rule out the presence of hyperopia.
How is farsightedness treated?
Farsightedness can be corrected with eyeglasses, contact lenses or refractive surgery.