Normally, the rays of light entering the eye are brought to a precise focus on the retina – the light sensitive layer lining the back of the eye. When such a focus is not achieved, a refractive error results and vision is not clear. These imperfections in the focusing power of the eye are called refractive errors.
The common refractive errors are
1. Myopia or Near sightedness
2. Hyperopia or Far sightedness
Myopia (Near Sightedness)
A Myopic eye is longer than normal or has a cornea that is too steep, as a result of which the light rays focus in front of the retina. Close objects look clear, but distant objects appear blurred.
Hyperopia is a term used to describe the condition of farsightedness. The causes of hyperopia are typically genetic and involve an eye that is too short or a cornea that is too flat, as a result of which images focus at a point behind the Retina. People with hyperopia can usually see distant objects well, but have trouble focussing on nearby objects
Astigmatism ( Distorted Vision)
ASTIGMATISM (cylindrical error) occurs when the incoming light rays are unable to reach a common focus within the eye. Astigmatism distorts or blurs vision for both near and far objects. The cornea is the clear front window of the eye. A normal cornea is round and smooth, like a basketball. When you have astigmatism, the cornea curves more in one direction than in the other, like a football. It is possible to have astigmatism in combination with myopia or hyperopia.
Learning that your child needs glasses can be an emotional experience. Some parents feel sad that their child’s eyesight is not perfect. Despite newer and more fashionable frames, glasses can seem like an intrusion on your little one's face. The key is to develop a positive attitude.
Help your child realize that the glasses will make an important difference in their eyesight. Your child will now have a chance to see better and get information more efficiently.
Parents who honestly believe that glasses are important for their child will have an advantage when it comes to getting the youngster to wear them.
Children may need glasses for several reasons – some of which are different than for adults
A child may need glasses to: • Provide better vision; to function better in his/her environment
Help straighten the eyes when they are crossed or misaligned (strabismus).
Help strengthen the vision of a weak eye (amblyopia or “lazy eye”). This may occur when there is a difference in prescription between the two eyes (anisometropia). For example, one eye may be normal, while the other eye may have a significant need for glasses.
Provide protection for one eye if the other eye has poor vision.
Early childhood is the most critical period of vision development.
Blurred vision in one or both eyes can prevent the visual system from developing properly.
Wearing glasses and seeing better is proven to improve school performance. That’s why it’s important for children wear their prescribed glasses.
This is a question most parents ask, especially when their child is an infant or toddler. The best answer is that most young children who really need glasses will wear them happily because they do make a difference in their vision.
Here are a few ideas to help get your child to wear glasses
Start by having your child wear glasses for short periods during enjoyable activities, when your child will be having so much fun that he or she will forget about them. Use the glasses as part of reward times, such as when your child is watching his or her favorite video.
Choose a time when your child is rested and in a good mood to start requiring the glasses.
If your child takes his or her glasses off, be sure you put them back on in a firm but loving manner.
If your child learns that he or she has control over wearing the glasses, you may lose the battle. You do not want taking off the glasses to be an attention-getting tool.
Check the fit of the glasses. Stop by the optical shop if the frame loosens. As the child grows, the glasses may become tight or uncomfortable. Glasses that are poorly fitted can easily slip and slide down, and they then become useless.
Be positive. Parents’ and grandparents’ attitude can influence a child more than you think. Make glasses "cool" for your child: point out pictures of sports stars or entertainers who wear glasses. For very young children, "being just like mommy or nana" may be what counts.
Compliment your child for remembering to wear his or her glasses
Give your child some say in selecting the frame. Select three or four different frames that are acceptable to you, and then let the child pick the one he or she likes best.
Make the glasses a part of the child's daily routine. Put them on in the morning as your child is getting dressed and remove them before naps and bedtime. Enlist the teachers help by telling them your child's schedule for wearing glasses.
Children usually need a few weeks to get used to new glasses or to an updated prescription. Often children who have a negative perception of glasses will claim they see blurry to avoid having to wear them. Only if he continues to complain after one month of consistently wearing the glasses should they be rechecked to make sure that they are accurate.
If your child has myopia or nearsightedness, then she will most likely need glasses for life or until she elects contact lenses as a teenager or refractive (LASIK) eye surgery as an adult (usually no sooner than age 18 to 21).
Since clear vision with eyeglasses is preferable to uncorrected vision, glasses wearers may find that they want to wear eyeglasses more often
Watching television or working on computers or video display terminals (VDTs) will not harm your eyes. Often, when using a VDT for long periods of time, just as when reading or doing other close work, you blink less often than normal.
This reduced rate of blinking makes your eyes dry, which may lead to the feeling of eye strain or reflexive excessive blinking.
There is some evidence that excessive indoor reading or viewing of VDT activities can increase myopia, so outdoor activity after school can balance against this.
Almost all children in the United States have an adequate, well-balanced diet including vitamins that are sufficient to promote normal eye health and growth.
The need to wear glasses is unrelated to the nutritional state of the body. It is nevertheless helpful to ensure plenty of green, leafy vegetables for healthy eyes and eyesight.
The prescription continues to increase because the eyes are growing. A naturally growing eye becomes more myopic or nearsighted. This is a normal developmental process, not a degenerative process.
There is no scientifically proven vision therapy that will prevent the need for glasses or decrease the rate of progression of the power of the glasses, or that will slow down eye growth, or reduce the strength of the glasses.