Infants and children with lazy eye experience a loss or lack of development of vision, usually in one eye. Lazy eye is caused by the physical limitations of the eye and the effect these limitations can have on the nerves leading to the brain. The three types of conditions that can lead to lazy eye are crossed-eyes, defects in the focusing power of the eye, and damage or clouding caused by cataracts or other diseases. In the treatment of this disease, the younger a child is, the more effective correction of vision tends to be. Parents have a special responsibility in seeing that prescribed treatment is closely followed so their children can look forward to a lifetime of good vision! “Lazy eye” describes a progressive loss of vision that occurs because of poor development in one or both eyes during infancy and childhood. Usually, only one eye is affected. Infants with lazy eye will make a fuss and cry if one eye is covered. Children with lazy eye may be able to see things well on one side, but have problems seeing all objects clearly and judging depth or distances. Consequently, they may try covering one eye or tilting their head to read. They may also be seen rubbing their eyes, winking or bumping into objects on the side of their weaker eye. Children with crossed-eyes often develop lazy eye. However, this degenerative condition may also develop without any very obvious signs, and the affected eye often appears perfectly normal. Lazy eye usually develops because of an inherited condition and is experienced by children. There is very little likelihood that lazy eye would develop in an adult. Lazy eye is caused by the degeneration of nerve connections between the brain and the eye during infancy and childhood. The process of degeneration usually begins when one eye’s physical limitations keep it from developing as it should, and the retina of that eye (the place where we “see”) no longer receives clear, well-defined images to transmit to the brain. There are three types of physical limitations that can lead to lazy eye: misalignment of the eyes (crossed-eyes), defects in the focusing power of the eye (nearsightedness, farsightedness and astigmatism) and damage or clouding caused by cataracts or other diseases. When the eyes are misaligned (crossed), a child may see double. The brain typically reacts to prolonged double vision by blocking out one of the images it perceives in order to see more clearly. As the dominant eye takes over more and more visual tasks, the nerve connection to the brain degenerates, and vision in one eye is lost over a period of time. A similar degeneration process occurs when focusing power is unequal, and one eye sends the brain an image that is in focus while the other eye sends an image that is out of focus. The brain will give preference to the clear image, and vision in the weaker eye will fade out. The condition of infants with eyes damaged or clouded by cataracts or other diseases follows the same process and may be particularly severe. In many cases, there is a very real potential for ongoing complications and recurrence of lazy eye. In all of the cases mentioned above, children should be treated without delay to avoid permanent loss of vision. Generally speaking, the younger children are, the shorter their course of treatment and the more successful the results are likely to be. Eye patching is the most frequently used treatment for strengthening a child’s “lazy eye,” regardless of age, while vision therapy (commonly called "orthoptics") is for children old enough to have good comprehension skills. Children with crossed-eyes may wear glasses to reduce their focusing effort and straighten their eyes. In this approach, patching the dominant eye for carefully monitored periods of time can help strengthen the weaker eye. Once focusing problems are addressed, some children with eye misalignment may require surgery (see Crossed-eyes) to reposition certain muscles around their eye(s) for permanently restored control. Vision therapy may be used at various points during treatment. Combination treatments can be used for children with focusing problems, including prescription glasses (with bifocal, prism, concave or convex lenses), monitored patching and vision therapy. Treatment for pre-adolescents, adolescents and adults is possible, but will take longer and is often less effective. In adults, treatment such as vision therapy may or may not improve overall eyesight. Whatever course of action is chosen, healthy adults who know they had lazy eye during childhood can rest assured that their vision will not deteriorate any further during adulthood. Children who have decreased vision in one eye do not necessarily have lazy eye. A qualified eye doctor can examine the inner eye and monitor your child to determine whether he or she has lazy eye, an eye disease or simply needs corrective glasses to focus better. The problem with lazy eye is that it is not always easy to recognize. Children are often not aware that one of their eyes is weaker than the other and may simply consider themselves clumsy or careless. For this reason, it is essential to see your eye doctor immediately if you suspect your child’s vision is abnormal or weakening. If eye disease or eye problems run in your family, make sure you schedule a checkup with an eye doctor before your child turns 3. Even children with no symptoms whatsoever should receive a complete eye examination by age 4. Once a course of treatment is prescribed, parents have a vital role to play in seeing it through. Children often do not enjoy having an eye patched, wearing glasses or doing vision therapy. But successful treatment depends on patience and perseverance. Can you guess the number one reason for blindness in children with lazy eye? Answer: prolonged, inconsistent or incomplete treatment. |
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