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HyperopiaEncyclopedia of Medicine by Lorraine LicaDefinitionHyperopia (farsightedness) is the condition of the eye where incoming rays of light reach the retina before they converge into a focused image. DescriptionWhen light goes through transparent but dense material like the materials of the eye`s lens system (the lens and cornea), its velocity decreases. If the surface of the dense material is not perpendicular to the incoming light, as is the case with the curved surfaces on lenses and corneas, the direction of the light changes. The greater the curvature of the lens system, the greater the change in the direction of the light. When parallel light rays from an object go through the lens system of the eye, they are bent so they converge at a point some distance behind the lens. With perfect vision this point of convergence, where the light rays are focused, is on the retina. This happens when the cumulative curvature of the lens plus cornea and the distance from the lens to the retina are just right for each other. The condition where the point of focus of parallel light rays from an object is behind the retina is called hyperopia. This condition exists when the combined curvature of the lens and cornea is insufficient (e.g., flatter than needed for the length of the eyeball). This condition can be equivalently described by saying hyperopia exists when the eyeball is too short for the curvature of its lens system. There is a connection between the focusing of the lens of the eye (accommodation) and convergence of the eyes (the two eyes turning in to point at a close object.) The best example is during reading. The lens accommodates to make the close-up material clear and the eyes turn in to look at the print and keep it single. Because of this connection between accommodation and convergence, if the lens needs to accommodate to focus for distance (to bring the image back onto the retina) the eyes may appear to turn in even when looking at the distance. This can cause a condition known as accommodative esotropia in children. The eyes turn in and the cause is accommodation because of hyperopia. Causes & symptomsBabies are generally born slightly hyperopic. This tends to decrease with age. There is normal variation in eyeball length and curvature of the lens and cornea. Some combinations of these variables give rise to eyes where the cornea is too flat for the distance between the cornea and the retina. If the hyperopia is not too severe the lens may be able to accommodate and bring the image back onto the retina. This would result in clear distance vision, but the constant focusing might result in headaches or eyestrain. If the lens cannot accommodate for the full amount of the hyperopia the distance image would be blurry. If the eyes are focusing for distance and now the person is looking at a near object, the eyes need to accommodate further. This may result in blurry near objects or headaches during near work. Depending upon the amount of hyperopia, symptoms can range from none to clear distance vision but blurry near vision, to blurry distance and near vision. Headaches and eyestrain may also occur, particularly when doing near tasks. An eye turned in (esotropia) may be a result of hyperopia, particularly in children. However, because a turned eye may be a result of more serious causes it is very important to have it checked out. DiagnosisBecause it is possible to have good visual acuity with some degree of hyperopia it is important to relax accommodation before the eye exam. This is done with the use of eyedrops and is called a cycloplegic exam or cycloplegic refraction. The drops relax the accommodation (thus making reading blurry until the drops wear off). Patients will usually be asked to have someone drive them home because of the blurriness. The doctor can then determine the patient`s visual status with a hand-held instrument called a retinoscope and/or have the patient read from an eye chart while placing different lenses in front of the patient`s eyes. Refractive error is measured in units called diopters (D). TreatmentThe usual treatment for hyperopia is corrective lenses (spectacles or contact lenses). Different surgical methods to correct hyperopia are under investigation. One approach is to implant corrective contact lenses behind the patient`s iris. The first experimental implantable contact lenses were implanted in 1997. Another approach is to surgically increase the curvature of the eye`s existing cornea or lens. Although there have been many reports of success using different kinds of lasers to increase corneal curvature, as of 1998 there are still problems with stability and predictability. The introduction of light-activated biologic tissue glue in 1997 holds promise for improvements in those areas. PrognosisThe prognosis for fully corrected vision is excellent for patient`s with low to moderate amounts of hyperopia. Patient`s with very high hyperopia (+10.00D or more) may not achieve full correction. Moreover, surgery to correct hyperopia will probably be perfected and approved in the near future. Hyperopia increases the chances of chronic glaucoma, but vision loss from glaucoma is preventable. PreventionHyperopia is usually present at birth, and there is no known way to prevent it. Key Terms
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BooksGale Encyclopedia of Medicine. Gale Research, 1999. The mind`s eye - Brief Article - InterviewPsychology Today , July-August, 2002 by Beverly EngelIn 1993, this photo appeared in a Philadelphia Magazine article about a typical American family. We decided to find out what happened to Ed Fischer and Ellie Fitzpatrick and their three sons, Patrick, John and Bobby. Today, nine years later, Ed and Ellie look at the photo and reflect on the changes in their lives. Marriage and family therapist Beverly Engel probes the rigors of family life through the eyes of Ed and Ellie. Ellie: I can remember when this picture was taken. It`s so vivid in my mind; it seems like yesterday, I`m in awe, though, of how much has changed. I`ve talked about those days, especially with my youngest son, Bobby. He mentioned that life was so much simpler then and that he wished he was still in preschool. In nine years, our lives have certainly become busier. The boys are now 16, 14 and 12. So there`s less time for Ed and me to read in bed. We`re always running around, taking this one to sport practice or another to a game or a school dance. But we still have quite a few moments when we`re all together in the same room. Ed: When the photo was taken, we lived in the suburbs, and now we live in a more urban area, near the Philadelphia city line. Now that Ellie and I live closer to work, we spend more time at home. Back then, on most weekday mornings, the kids would join us in our bedroom and they`d cuddle with us and play together. Of course, now they sleep as late as possible. The boys still do things together, like play basketball and watch movies. They`re friends. We`re really blessed in that way. Ellie: Sure there are disagreements and rivalries, but in general, the boys get along and they like the same things. We feel that we`re close as a family. Ed and Ellie obviously have done the right things as they raised their sons--lots of nurturing and lots of quality time together. And they are doing the right things now. While we all sometimes fantasize about a simpler time, they`ve learned to appreciate what they have today and to look for the good. They may not have the time they once had to relax together, but their boys are active, they get along with each other and they are still close to their family. That`s a lot to be grateful for. Marriage and family therapist Beverly Engel has written numerous books about relationships including Loving Him Without Losing You. COPYRIGHT 2002 Sussex Publishers, Inc. COPYRIGHT 2002 Gale Group Eyes relaxation index
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