What Is farsightedness?
Farsightedness, or hyperopia (medical term), occurs when the focal length of the cornea and the lens together is too long to focus an image on the retina. This results in the image being focused behind the retina. This causes objects that are close to the eye to become blurry when they are imaged on the retina.
The focusing system of the eye, which is called accommodation, will try to focus the large lens behind the iris and pupil to make things clearer. This creates eye strain as the eye tries to focus on near objects. The ciliary muscles will try to focus, get tired and then try again. If the near demand is too much, the muscles give out and vision remains blurry. Many patients will often complain of intermittent blurriness, with increasing blur at near.
This scenario is what happens to young people with good focusing ability and with relatively low amounts of hyperopia. In people with higher amounts of hyperopia, older adults, or individuals who can't focus at all, vision will be blurry for near and for distance. This is why "farsightedness" is a less than optimal description of hyperopia.
Presbyopia, or being unable to read up close after the age of 40 is an age related variation of hyperopia. As we get older we lose the ability to focus our eyes and by the fifth decade our focusing is almost completely gone.
What causes farsightedness?
Most people who are farsighted are born with it, but it may not cause vision problems until they get older. While there's no clear evidence for hyperopia inheritance, your risk for hyperopia is greater if you have siblings or parents with hyperopia as well. Most children are born being slightly farsighted.
What are the symptoms of farsightedness?
Many younger farsighted people will not notice any problems at all with their vision. If they have to start straining their eye muscles to see, they may complain of the following symptoms: blurred vision, especially at near, difficulty reading, eye strain, eye pain and dull headaches.
Treatment for farsightedness
Glasses and or contact lenses can be used to correct for hyperopia.
Patients need to be aware, however, that as the amount of hyperopia increases, the thickness of the lens increases as well leaving the patient with glasses that makes their eyes look very large or "bug-eyed".
Eyeglass lenses should be aspheric to reduce thickness and weight and anti glare coated to reduce disturbing reflections.
Cosmetically, contact lenses are usually a better option in these cases. There are many choices of soft or rigid gas permeable (RGP) contact lenses that can be used for farsightedness.
Older adults will always need bifocals, progressives or two pairs of glasses to see far and near if they are farsighted.
LASIK is also an option for very low amounts of farsightedness. The LASIK procedure for hyperopia involves removing much larger amounts of corneal tissue than it does in myopia. This creates a more risky procedure with more postoperative complications.