Hyperopia (farsightedness) is a condition of the eyes in which distant objects are in clearer focus than objects closer to the eye, which appear blurry. The eye is designed to focus images directly on the surface of the retina; with hyperopia, light rays focus behind the surface of the retina, producing a blurred image. Hyperopia, which is often inherited, occurs if the eyeball is abnormally short, the cornea has too little curvature, or the lens is situated too far back in the eye.
In addition to the anatomical causes mentioned, farsightedness can be caused by certain eye diseases, or weakened focusing power.
Symptoms of Hyperopia
People with hyperopia are often unable to keep close objects in focus, which can make maintaining concentration difficult. They may also have some or all of the following symptoms:
- Eye strain or fatigue
- Trouble reading fine print
- Difficulty performing tasks requiring close focus
- Headaches after reading or other close work
- Aching or burning eyes
- Blurred vision, particularly at night
Young children with hyperopia may have no symptoms. In severe cases, however, it can cause the following:
- Frequent eye-rubbing
- Trouble with, or lack of interest in, reading
Children with hyperopia may also exhibit symptoms of strabismus (crossed eyes).
Diagnosis of Hyperopia
A comprehensive eye examination is necessary to detect hyperopia. Parents should be aware that typical vision screenings performed in schools do not usually detect farsightedness. During a thorough eye examination, the following tests may be performed in order to definitively diagnose any visual problems:
- Slit-lamp examination
- Visual-acuity exam
- Examination of the retina
- Refraction test
- Glaucoma test
- Dilated-eye examination
For some types of vision tests, drops are administered to dilate the pupils. In some cases, a stain (fluorescein) is administered to provide a more delineated view of the cornea.
Treatment of Hyperopia
For a great many people who are farsighted, the condition does not present any real problem since they are able to adjust their focus well enough to function without difficulty. In more severe cases, however, prescribed corrective lenses, worn as eyeglasses or contact lenses, may be necessary, although they are usually worn only for reading or other close work. Most people with hyperopia require prescription lenses as they get older, because hyperopia worsens during the aging process.
Surgery is also a treatment option for patients with hyperopia. In mild cases, surgical procedures to reshape the corneas may be performed. Two common ones are LASIK (laser-assisted in situ keratomileusis) and PRK (photorefractive keratectomy). When farsightedness is severe, the lens of the eye can be replaced with an implanted lens.