Hyperopia is characterized by foreshortened eyeball, in which light is focused behind the retina instead of on it, causing images to look fuzzy. The shorter your eyeball is, the farther away the retina will be from the point at which the light is focused, and the blurrier your vision will be.
Hyperopia and myopia are called refractive errors because the light doesn’t bend properly as it moves through the eye. This kind of problem is said to be mechanical, or related to a physical mechanism, as opposed to pathological, or related to a disease process. (For more on refractive errors, see Astigmatism.)
People with hyperopia have trouble seeing objects close to them- without the aid of contact lenses or glasses, they have a heck of a time doing things like plucking their eyebrows or trimming their goatees. The word "close" is relative, of course. A person with moderate to severe uncorrected hyperopia may not be able to see well enough to hit the golf ball at their feet or even to make out the flag on the putting green.
Symptoms of hyperopia include the following:
- Blurred vision at close or intermediate range or both
- Eye strain, fatigue, or headaches when reading or doing other near work
- Headaches or aching eyes
- Inability to sustain concentration
Environmental influences such as stress, nutrition, and general health may have some say in whether you develop hyperopia, but most of the votes have been cast before you’re born. Your genes pick up the blueprint, and your cells construct your body organs and systems according to plan as you grow and age. Heredity and aging, in fact, are the only real risk factors for hyperopia.
People with a marked degree of hyperopia or myopia do tend to develop glaucoma more frequently than other people. It’s especially important, then, for them to learn about the condition and to have regular comprehensive dilated eye examinations
Your vision care provider uses a simple visual acuity test and refraction testing to diagnose hyperopia.
Visual acuity testing. Most of us are familiar with the "big E" visual acuity chart, so named for the large block letter that usually appears at the top. Officially, it’s known as the Snellen eye chart, named for the ophthalmologist who invented it in 1863. It helps your provider determine how well you see at various distances.
Refraction testing. Refraction testing is the process of measuring how the eye focuses light. It’s done with the aid of a phoropter, a specialized instrument that resembles a pair of oversized goggles hanging from a boom. The goggles conceal a series of lenses your eye care provider adjusts as you read the letters on a projection screen, choosing stronger and stronger lenses until the letters look crisp.
As part of a comprehensive examination, your provider will probably also measure fluid pressure in your eyes and dilate your pupils to check the health of the internal structures of the eye, including the retina.
Hyperopia is expressed in diopters, a measure of refraction, or the power of a lens to bend light. Myopia is indicated by a negative sign before the number, whereas hyperopia is designated by a positive number. The farther away from zero the number is, the more hyperopia you have. If your right eye measures 1.5 diopters and your left eye measures 3.0 diopters, then your left eye is more hyperopic than your right.
Vision can be corrected with glasses, contact lenses, refractive surgery, or intraocular implants.
Eyeglasses. Eyeglasses are nothing fancy, but if you have hyperopia, they might come in handy at your next garden party when you’re trying to tell if those are ants or caraway seeds on the finger sandwiches.
Contact lenses. Rigid or soft contact lenses are also effective in correcting hyperopia. For people who have hyperopia with astigmatism, toric lenses-soft contacts with two powers in them, like bifocals-might be a good option.
Refractive surgery. The goal of refractive surgery is to reshape the cornea as an alternative to wearing contacts or glasses.
Laser surgery. Methods of refractive surgery include various laser procedures, such as LASIK surgery and photorefractive keratectomy (PRK). (read: Understanding Lasik to learn more).
Hyperopia and Age
About one fourth of all people in the U.S. are farsighted. Many of us consider it to be a sign of aging, but children often have hyperopia, too. Most of them, though, are able to successfully accommodate for having a slightly off-target focal point by unconsciously contracting or relaxing their eye muscles to change the shape of the lens.
Some accommodation is natural and improves our vision. When one or both eyes turn too far inward, toward the bridge of the nose, a kind of strabismus called accommodative esotropia may be present. This condition, commonly referred to as "crossed eyes," usually calls for corrective hyperopic spectacle lenses or surgical correction if glasses do not correct the strabismus fully.
It's true, though, that the prevalence of hyperopia is heavily skewed toward people age 60 or older. The reason is simple-as we age, the structures of the eye become less elastic, and the surrounding musculature can no longer effectively accommodate for the hyperopia that has been present all along.
Some children with moderate to severe hyperopia are unable to compensate for it well enough to see adequately. They may have trouble learning to read, or they may be fidgety when doing long division, practicing their handwriting, or carrying out any other task requiring sharp near vision. Vision screenings done at school are intended primarily to identify kids with myopia, so it’s important to make sure children have periodic comprehensive eye examinations performed by a qualified vision care professional, especially if they’re having difficulty paying attention. They might just be having trouble, well . . . focusing.