The eyes are our most important sensory organ, 80% of the external information is obtained through our vision, is the first element of people’s life, learning and work. If the eyesight is poor, it will not only seriously affect the physical and mental health of children, but also affect their future education, military and employment. The latest survey results show that: the overall prevalence of myopia in China is 40%, 40% to 60% for children, and according to the 1.3 billion population, our country has 500 million myopic eyes! Among them, 2~3 % are highly myopic.
At present, the age of myopia prevalence has a tendency of low age. Therefore, myopia has become a public health problem of common concern at home and abroad.
Our eyes are like a camera, with the cornea and lens constituting the “lens” and the retina constituting the “film”. The distance between the lens and the film is the length of the eye axis. During the normal development of the eye, the development of the various “parts” of the eye should be coordinated and balanced with each other, and if they are well matched, our eye will develop into an ortho-optic eye, which is the process of orthokeratology. If any one of these “components” is abnormal, the other “components” cannot compensate effectively, resulting in refractive error (myopia, hyperopia, astigmatism).
The eye axis is a key factor in determining refractive status. The average length of the eye axis of our newborn babies is 17mm; it grows to 21mm at the age of 3, 22.5mm at the age of 6, and 23.5mm at the age of 16~18, basically reaching the length of the adult eye axis.
Figure 1: The left is the size of a normal eye, and the right is the size of an eye with high myopia, with significant differences between the two.
I. Pathogenic factors of myopia.
Current research confirms that the interaction of genetic and environmental factors is an important cause of myopia.
The occurrence and development of myopia is closely related to the individual’s physical condition. Current research data and statistics show that if one of the parents is highly myopic, the offspring will have an epiphenomenon rate of 50%, and if both parents are highly myopic, the offspring will have an epiphenomenon rate of 80%. A total of 14 pairs of myopia genes have been identified. There are two types of inheritance: dominant and recessive. Just like my height, the genetic constitution determines the height of our height, the eye axis determines the degree of myopia.
For every millimeter of growth in the eye axis, myopia increases by 250 to 300 degrees. One of the most important signs that a child with myopia is genetically gifted is that the length of the eye axis is significantly longer than that of children of the same age, and may even exceed the normal adult eye axis length.
Early and excessive eye use at close range, such as improper posture for homework, excessive reading time, playing with cell phones, computers, game consoles, practicing piano, playing with small toys, etc., cause excessive visual near load and are the main environmental factors that induce myopia.
The best conclusion of myopia etiology is that the poor eye environment increases the epiphenomenon and expressivity of myopia genes during the period when the child’s eyes are developing fastest and most unstable, and therefore, eventually leads to myopia occurrence. Excessive eye use at close range is the catalyst for the myopia gene. To use an analogy, a person with a poor constitution will get sick at the slightest exposure to wind and rain. A person with a strong constitution, on the other hand, will not get sick easily.
Different body types have different sensitivities and resistances to adverse external environmental influences. The formation of myopia also has similar characteristics: some children read books and play with computers every day, but their eyes are not prone to myopia; while some children do not take long to experience vision loss. People with myopia genetic constitution are more obviously affected by bad eye habits. Not only is the age of onset early, but myopia progresses faster and the chances of developing into high myopia are greatly increased. It is very common for myopia to increase by 100 to 150 degrees per year in elementary school students, and even in some individuals myopia increases by more than 200 degrees per year, so extra attention must be paid.
Figure 2: The incidence of myopia in the offspring of both parents with myopia is 6.4 times higher than that of both parents without myopia. The incidence of myopia gradually increases with longer working hours in close proximity.
The dangers of myopia
The treatment of myopia is not just a matter of wearing a pair of glasses. Mild myopia does not affect our eyes much, but patients with high myopia over 600 degrees are prone to complications such as macular degeneration, hemorrhage, fissure, retinal degeneration, detachment, etc. The incidence of glaucoma and cataract is also higher than that of normal eyes, and its chance of leading to low vision and even blindness is many times higher than that of normal eyes, accounting for 20% to 30% of the causes of blindness and low vision. Moreover, the above lesions often occur gradually after middle and old age (average age of onset is 50 years), which seriously affects people’s quality of life.
Figure 3: The horizontal coordinate indicates the refractive error from 0 to -14.00 degrees; the vertical coordinate indicates the chance of myopia complications. The incidence of myopic complications within -4.00 degrees is very small and almost zero, but after 4.00 degrees, the incidence of myopic complications increases significantly, especially for myopic eyes with more than -8.00 degrees, and the incidence of complications increases linearly.
III. Preliminary diagnostic criteria for pathological myopia in children.
< 5 years old >-4.00 degrees; 6 to 8 years old >-5.00 degrees; 9 to 11 years old >-8.00 degrees
12 to 18 years >-10.00 degrees
High myopia fundus complications
Retinal detachment Macular hemorrhage
Macular fissure Pathological myopic fundus changes
Fourth, the principle of myopia treatment: prevention and control
At present, there is no cure for myopia, but myopia can be prevented and controlled, but the key is one word: early! To achieve early prevention, early detection, early treatment. We would like to remind parents here that having the right perception often has a huge impact on their children’s future. The prevention of myopia should start at an early age, children should develop good eye habits after birth, do not read books, play with cell phones, play with computers too early, too much. 3 years old after regular health check-ups at regular, professional eye clinics or eye hospitals.
After myopia, myopia will continue to deepen with age. 6 to 16 years old is the fastest growing period of the body, and is also the period when children go to school and use more eyes, which is a high-risk period for myopia. The current medical level cannot accurately predict the degree of myopia development in children in the future, but there are always some rules to follow, such as: two or one parent with high myopia, long eye axis, early onset of myopia, etc. Children with two or more conditions will have a clear genetic predisposition to myopia and a higher susceptibility to myopia.
The chance of developing high myopia or even pathological myopia in the future will be higher due to the influence of the adverse external environment! Don’t let your child’s eyes become highly myopic or even pathologically myopic for the rest of his or her life. Therefore, you should actively take measures to prevent and control the development of myopia is the most fundamental and important. Usually do less near, more far, more daytime outdoor activities (for every 1 hour increase in outdoor activities, the refractive error is 0.17D towards hyperopia, and the eye axis is shortened by 0.06mm;), balanced nutrition, less sweets and drinks, try to make children’s myopia occur later, myopia deepen more slowly, the future degree shallow, to avoid the occurrence of adverse consequences.
1.Optical intervention.
(1) keratomileusis (OK lens). The world’s medical centers for more than 50 years of clinical application and research, confirmed that the party hair safe and effective.
(2) Multifocal corneal contact lenses.
(3) RGP lenses.
(4) Multifocal lenses (bifocals, progressive lenses).
(5) Reading lenses, undercorrection, prismatic lenses.
(6) Posterior scleral reinforcement.
2. Pharmacological interventions.
(1) Atropine. (Some studies have found that atropine is very effective in controlling myopia, but its clinical use is limited due to its many side effects.)
(2) Pirenzepine.
3. Other.
(1) Eye care strategies.
(2)Outdoor activities or just staying outdoors.
4. Comparison of the effectiveness of different correction forms for myopia control in children: keratomileusis, progressive multifocal glasses, RGP, and frames;
Figure 4: Clinical study from Wenzhou Medical College, comparing the effect of different correction methods on the control of myopia in children, four methods of continuous observation for two years, found that the growth rate of the eye axis of the corneal plastic lens group is the slowest, can achieve the effect of slowing down 50% to 60%. The slower the growth of the eye axis, the slower the progression of myopia and the lower the risk of complications. (1mm eye axis growth, refractive error growth of 250 to 300 degrees).
Are all of the above methods suitable for all myopic children and adolescents?
There is no one-size-fits-all treatment, and treatment must be tailored to the individual and must be determined through a series of tests.
Through binocular visual function tests, it is found that most myopic patients have not only poor accommodation but also significant accommodation lag. The correct approach is to perform accommodation training, including flip-tap and lens sequencing. For adjustment problems caused by abnormal pooling function need to address the pooling problem, for insufficient or too strong need to be respectively polyphthalmia training or give ADD prescription glasses.
Figure 5: Working too close to the eye, decreased contrast sensitivity can lead to accommodation lag, and a higher degree of accommodation lag leads to the growth of the eye axis and a deepening of myopia.
The second key issue in myopia control is peripheral retinal hyperopic defocus. The peripheral retina plays an important role in the development of the eye and is in hyperopic defocus during traditional optical correction, which may be the reason for the progression and progression of myopia. The problem of peripheral retinal defocus can now be solved with keratoplasty, multifocal keratocontact lenses and RGP, which have been clinically used and studied and found to be the most effective in controlling the rapid growth of myopia.
Figure 6: Farsighted defocusing of the peripheral retina leads to focal growth of the sclera, growing eye axis, and increasing myopia.
Keratomileusis changes the mid-peripheral corneal morphology to reduce or eliminate mid-peripheral retinal hyperopic defocus, thus effectively curbing the rapid growth of the eye axis and slowing the rapid progression of myopia.
Children with high myopia or myopia whose eye axis growth cannot be effectively controlled by other methods may opt for posterior scleral reinforcement. This is also no way out.
Six, as the saying goes, three points of treatment and seven points of care. Normally, good eye habits should be cultivated.
1, sit upright, chest from the table a fist, eyes from the reading material a foot, fingertips from the pen tip an inch.
2. Do not read continuously for a long time, and take a break and look away for 10 minutes between classes or after 30-40 minutes of continuous study. Do not read in a car, on foot, in bright light or in bed.
3. Look at the computer from a distance of 50cm, once or twice a week, for 20-30 minutes each time. Watch TV at a distance of 2 meters away, preferably not more than 1 hour a day. Can not play mobile games or read with cell phones.
4, balanced nutrition, less sweets, drinks.
5.Participate in outdoor activities regularly, have 2 hours of daytime outdoor activities every day, and preferably more than 18 hours of daytime outdoor activities every week.
6.Check your vision regularly and correct any abnormalities in time.
The prevention and treatment of myopia requires the joint efforts of families, schools and the whole society. At present, there are various treatment methods in the society, so parents are advised not to rush to the doctor and choose inappropriate treatment methods. The best time to treat your child will be missed, leading to lifelong regrets. Myopia can be prevented and controlled, but it is important for parents to have the right knowledge.
Early prevention, early detection, early treatment!
Figures 1~6 above are provided by Bear, a German myopic eye scientist.