How to treat myopia in children and teenagers?

Author: Zhang Xiaohui Source: Science New Life

How to treat myopia in children and teenagers?

The summer vacation of 2024 is here, and the hospital's optometry clinic has started to line up again. Students and parents come to the hospital for optometry, glasses, consultation and eye examinations. my country has the highest incidence of myopia in the world and has the largest number of myopic people. Myopia surgery is for people over 18 years old, and the myopia degree has been stable for more than 1 year. For adolescents and children who do not undergo surgery, there are various treatment options for myopia.

Should I choose frame glasses or orthokeratology lenses? Are contact lenses orthokeratology lenses? What are myopia prevention lenses? Are there any eye drops that students usually use that can fight fatigue? These are questions that parents and students urgently need to know.

The main cause of myopia is that the eye axis is too long and the image is formed in front of the retina. The longer the eye axis, the higher the corresponding myopia degree, and the "balloon" of the eyeball will be blown bigger and bigger, causing obvious traction and continuous thinning of the retina. This is also the reason why patients with high myopia are more prone to fundus problems such as retinal tears, retinal detachment and macular degeneration. Children and adolescents are still in the growth and development stage, and the eye axis will continue to grow until the age of 23 to 25. At the same time, the eye axis of myopic children grows faster than normal children. Therefore, the treatment of myopia in adolescents is not only to correct myopia and see clearly in the distance, but more importantly to control the progression of myopia, that is, to slow down the growth rate of the eye axis.

The first choice is orthokeratology, also called OK lenses, which are effective in controlling myopia in people aged 8 to 16. It is a specially designed hard corneal contact lens that is worn at night and removed during the day. It changes the shape of the cornea and flattens the central area of ​​the cornea to reduce myopia. It is currently believed that orthokeratology lenses can change the peripheral defocus state of the retina, thereby inhibiting the growth of the eye axis. OK lenses are Class III medical devices and must be fitted by an ophthalmologist in a regular medical institution, and the cornea must be checked regularly. Studies have shown that the effect of OK lenses in controlling the growth of the eye axis is 43% to 63%. Not everyone can achieve good results after wearing orthokeratology lenses. There are individual differences in the wearing effect. Parents are reminded to go to regular institutions for fitting and outpatient follow-up to observe the effect and the impact on the eyes.

The second is myopia prevention and control glasses. In principle, it is a defocus lens, which is a myopic defocus produced by a special optical design on the lens, rather than delaying the growth of the eye axis and controlling the progression of myopia by changing the corneal morphology or drug intervention. Myopia prevention and control glasses are based on ordinary single-focus frame glasses, which move the peripheral focus forward, similar to the principle of OK glasses in controlling myopia. The biggest difference between the two is that defocus glasses have multiple focal points, which can prevent light from being projected onto the peripheral retina when worn. Defocus glasses can be divided into multi-point defocus glasses and peripheral defocus glasses. Both have a certain myopia control effect, and the overall control effect is lower than OK glasses.

Finally, many people choose frame glasses. The degree of glasses is determined by repeated eye examinations. In principle, the minimum degree that achieves the best vision is the standard. For example, if a person wears 1, 1.5, and 2 diopters of myopia lenses, and the vision can reach 1.0, then a 1 diopters lens should be selected, commonly known as 100-degree myopia, and a 2 diopters lens should not be worn. If the degree selected is too large, the eyes need to adjust hard when looking at close objects, and the ciliary muscles are easily fatigued, which will cause eye discomfort when working or reading at close range.

The method of choosing myopia glasses includes the following considerations:

First, choose a light frame. Since the frame needs to be on the nose for a long time, its weight should be given priority. Choosing a small frame can reduce the weight of the glasses. In addition, the center distance of the frame cannot be too different from the pupil distance.

Second, the degree of myopia should be determined through mydriasis refraction. If the normal naked eye without glasses has a distance vision lower than 0.8, a mydriasis refraction examination is required. Children under 12 years old need mydriasis refraction with atropine or homatropine, and those over 12 years old need mydriasis with tropicamide eye drops.

It should be emphasized that mydriasis is harmless to the eyes and can put the eyes in a resting state. The purpose of mydriasis is to relax the over-contracted intraocular muscles, namely the ciliary muscles, to remove the so-called pseudomyopia component of accommodative myopia and obtain accurate myopia refraction.

The methods of optometry include comprehensive ophthalmometer, computer ophthalmometer and manual retinoscopy. Through different optometry methods, the results are comprehensively judged and finally the accurate myopia refraction is obtained.

Third, glasses should be replaced in time. Myopic patients are advised to replace their glasses every 1.5 to 2 years to adjust the degree and "upgrade". Once the glasses are scratched, it will significantly affect its optical correction performance.

Fourth, you should choose the right lenses. Currently, the lenses on the market are mainly optical glass and resin. Glass lenses are cheaper and scratch-resistant, but they are fragile; resin lenses are light and not easy to break. In addition, you need to pay attention to the refractive index of the lens. For the same degree, the higher the refractive index, the thinner the lens. Generally, if the degree is high, try to choose lenses with a high refractive index, so that the glasses will be lighter. Contact lenses are frame glasses converted into corneal contact lenses, which are worn during the day and removed at night. They have no effect on myopia control. Contact lenses are mainly used for children with severe monocular myopia and are usually not the first choice for myopia treatment.

Many studies in recent years have shown that atropine eye drops with a concentration of one part per ten thousand (0.01%) can effectively slow the progression of myopia. The drug is currently being gradually introduced into China and has been officially launched in the country.

Myopia treatment cannot be a one-time solution. Adolescents are in the development period of their eyes and bodies. At the same time, they are constantly changing and are affected by the external and internal environment. Myopia treatment cannot expect one method to solve all problems. For adolescents and children, preventing myopia is the first priority. The methods include "one increase, one decrease, and two appropriate":

The "one increase" is to increase the time of outdoor activities, ensuring that the outdoor exercise time exceeds 2 hours every day. Table tennis exercises the ciliary muscles in the eyeball and is one of the outdoor activities with a very good effect on myopia prevention and control. Outdoor light can help children's vision development and also give the eyes a rest. Exercise can also increase local blood circulation in the eyeball.

"One reduction" means reducing sugar intake. Excessive sugar intake, including beverages, candies, pastries and cakes, has been proven to be one of the important causes of myopia in adolescents and children during their development period.

"Two appropriate" means using eyes appropriately. When reading or using electronic products, let your eyes rest for 10 minutes every 40 to 50 minutes. You can look into the distance, turn your eyeballs or do outdoor activities to give your ciliary muscles a rest and relieve visual fatigue. The distance should be appropriate. When reading or writing, pay attention to the height ratio of the desk and chair. ■

(Author's unit: Department of Ophthalmology, The Second Affiliated Hospital of Xi'an Jiaotong University)