On the harm of undercorrected or overcorrected myopia in children

Abstract: under correction of myopia refers to wearing glasses with a lower degree than they should be, This will make the corrected visual acuity of myopic people lower than normal (less than 1.0). In particular, children’s binocular visual function is not stable. They must have clear vision and correct eye habits to maintain their stable functional development.

Myopia can be corrected with a pair of appropriate glasses, but if the degree of glasses exceeds the myopia of the eye itself, over correction will occur. Myopia overcorrection will bring a lot of pain and harm, which should be avoided as far as possible. Today, I’d like to talk about the harm caused by over correction or under correction of myopia.

the main harm of myopia overcorrection

overcorrection causes eye discomfort

a suitable myopia lens can move the object image in front of the retina just back to the retina, so as to correct myopia and improve vision. However, over corrected myopia can move the object image in front of the retina to the back of the omentum, resulting in an artificial hyperopia state. At this time, what falls on the retina is only a blurred image. However, in our eyes, there is a complete regulation system. Relying on the contraction of ciliary muscle and the expansion of lens, we can move the object image behind the retina forward to the retina, which can still maintain good vision (of course, this regulation has a certain limit). However, if you over regulate for a long time, the ciliary muscles will be in a state of tension, contraction and congestion for a long time, and then regulatory spasm will occur, which will often make the eyes feel bloated, acid sleepy, fatigue and pain, and even lead to head distension, head tightness and headache. A few people will also have systemic symptoms such as inattention, memory decline, forgetfulness and insomnia, just like neurasthenia. Due to the inappropriate degree of glasses, many children also have a decline in academic performance.

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promote the development of myopia.

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have long-term adjustment tension and adjustment spasm. In addition, with long-term close eye use, the eyes are in a state of aggregation for a long time (the eyes move within a short time). The extraocular muscles have a certain compression effect on the eyeball, which will increase the intraocular pressure. Over time, it will promote the expansion of the eyeball wall and the extension of the ocular axis, It will undoubtedly increase the degree of myopia. This is especially harmful to children and adolescents who are in the period of growth and development.

the main harm of myopia under correction

myopia under correction refers to wearing glasses with a lower degree than they should be, This will make the corrected vision of myopia people lower than normal (less than 1.0). In particular, children’s binocular visual function is not stable, so they must have clear vision and correct eye habits to maintain the stable development of their function. Wearing uncorrected myopia glasses will make children unable to get clear vision, so that their vision can not get the due development, and make them use less adjustment force and collection force than normal when looking close. In the long run, their eyes will be damaged The decline of visual function leads to problems such as visual fatigue and accelerated growth of myopia. The defocus hypothesis of

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myopia holds that retinal blurred image will stimulate the eyeball to produce some factors regulating eyeball growth, and then make the eye axis grow improperly, lose the accuracy of coordination and matching with eyeball refractive power, and lead to the occurrence and development of myopia. After undercorrected eyes, the retina is also a blurred image, so it is in line with the defocus hypothesis.

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previous studies have shown that binocular vision has a certain impact on the progress of myopia. The growth rate of the degree of wearing foot corrected glasses in myopia children with normal eye position and exophoric deviation is slower, while children with endophoric deviation have no such effect.

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juvenile myopia should be corrected timely and appropriately. In case of low correction due to uncomfortable audition, The corrective glasses should also be adjusted to normal vision as soon as possible (2 ~ 3 months) to avoid adverse effects on eye diopter and eye position due to under correction. Optometrists must persuade most parents to change their wrong view that “myopia will deepen more and more” and do their duty to protect teenagers’ vision.

four prevention rules for over correction and under correction of myopia

1. For children and adolescents, mydriasis optometry is best used. Mydriasis can eliminate the adjustment and adjustment spasm, so as to avoid overcorrection.

2. There is no need to ask too much for corrected vision: the corrected vision with glasses should generally not exceed 1.0, and it is appropriate to be able to see the blackboard words in class at about 0.8. Do not blindly meet the requirements of children wearing glasses. They often hope that the clearer the vision with glasses, the better.

3. Check the audition prescription: the audition before matching is very important. It must be serious and have sufficient trial time, generally more than half an hour. Audition to achieve four “see” and “move”. “Four looks” means looking far, near, sky and earth; “Hyperactivity” means to walk, move, go up and down steps, move, twist your head, adapt, experience and observe carefully until you really don’t feel any discomfort.

4. Do not buy finished myopia glasses at will in the market. Because the finished lenses on the market are often lenses with equal binocular power and no astigmatism, it is difficult to adapt to everyone’s specific situation, and it is easy to be insufficient or overcorrected.